11-7 Conz & Pleasant Functional Design Report Nitsch Engineering

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Functional Design Report

Pleasant Street (Route 5) & Conz Street

Northampton, MA

July 2011

Prepared for:

Massachusetts Department of TransportationHighway Division, District 2 Office

811 North King Street

Northampton, MA 01060

Submitted by:

Nitsch Engineering186 Lincoln Street, Suite 200

Boston, MA 02111

Nitsch Engineering Project #8126.02


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TABLE OF CONTENTS

1 INTRODUCTION ............................................................................................................................................ 1

2 EXISTING CONDITIONS ............................................................................................................................... 2

2.1 Study Area............................................................................................................................................. 2

2.2 Traffic Volumes ..................................................................................................................................... 3

2.3 Seasonal Adjustment and Background Growth .................................................................................... 7

2.4 Crash Data ............................................................................................................................................ 8

2.5 MUTCD Signal Warrants ....................................................................................................................... 9

2.6 Road Safety Audit ................................................................................................................................. 9

3 PROPOSED IMPROVEMENTS ................................................................................................................... 10

3.1 Geometric Layout ................................................................................................................................ 10

3.2 Level of Service Criteria ...................................................................................................................... 17

3.3 Capacity Analysis Results ................................................................................................................... 17

3.4 Environmental Impacts ........................................................................................................................ 20

4 CONCLUSIONS ........................................................................................................................................... 21

5 TECHNICAL APPENDIX.............................................................................................................................. 22


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LIST OF TABLES

Table 1 Traffic Data Summary ........................................................................................................................... 4Table 2 Crash Data Summary ........................................................................................................................... 8Table 3 Crash Rate ............................................................................................................................................ 8

Table 4 MUTCD Signal Warrants Summary...................................................................................................... 9Table 5 Level of Service for Intersections ........................................................................................................ 17Table 6 Level of Service Summary 2011 Existing Conditions ...................................................................... 17Table 7 Level of Service Summary 2021 No Build ....................................................................................... 18Table 8 Level of Service Summary 2021 Build ............................................................................................. 19Table 9 Evaluation of Alternatives ................................................................................................................... 20

LIST OF FIGURES

Figure 1 Project Locus ....................................................................................................................................... 1Figure 2 2011 Existing Traffic Volumes ............................................................................................................. 5

Figure 3 2011 Existing Heavy Vehicles ............................................................................................................. 6Figure 4 Unsignalized & Signalized Intersection Configuration ....................................................................... 12Figure 5 Roundabout Alternative 1 .................................................................................................................. 13Figure 6 Roundabout Alternative 2 .................................................................................................................. 14Figure 7 Roundabout Alternative 3 .................................................................................................................. 15


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1 INTRODUCTION

Nitsch Engineering has prepared this Functional Design Report (FDR) to review existing traffic operations and to

propose design alternatives for the intersection of Pleasant Street (Route 5) and Conz Street in Northampton, MA.

The intersection falls within the purview of the Massachusetts Department of Transportation (MassDOT),

District 2, and the agency oversees its operations and maintenance.

The intersection of Conz Street and Pleasant Street (Route 5) in Northampton was among MassDOTs Top

1000 Crash Locations from 1997 1999. Shortly thereafter, the City of Northampton solicited planning

assistance from the Pioneer Valley Planning Commission (PVPC) which issued the Pleasant Street Safety

Transportation Study in June 2005. The study found that during the three-year period from 1999 to 2001, the

intersection had a crash rate of 1.66 accidents per million entering vehicles (acc/mev) which was significantly

higher than the statewide average of 0.66 acc/mev. The study concluded that the overall safety of the

intersection would increase with the installation of a traffic signal or a modern roundabout to provide greater

traffic control and operation within the intersection. MassDOT has begun the process of implementing

improvements to this intersection by authorizing Nitsch Engineering to proceed with engineering analysis and

the preparation of this FDR. Figure 1 shows the project locus and the surrounding area.

Figure 1 Project Locus


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speed limit of 35 mph. Speed data collected at the intersection indicates that vehicles traveling northbound have an

85th percentile speed of 39 mph. Sidewalks are absent on both sides of the roadway. Approximately 200 feet south

of the intersection, a guardrail starts to separate Pleasant Street (Route 5) from adjacent properties due to the

rising elevation of Pleasant Street (Route 5).

Pleasant Street (Route 5) north of the intersection also consists of

one 20-foot travel lane in each direction with a large grass median

separating the northbound and southbound lanes at the intersection.

A double yellow centerline separates bi-directional travel, and a

single white edge line separates a 2-foot shoulder from the traveled

way. There is no crosswalk on this approach. A grass strip

separates the shoulder from a 4-foot wide sidewalk on the east side

of the roadway. The pavement is in moderate condition with minor

cracks. Pavement markings are faded but visible. Similar to the

northbound approach, the speed zone regulation is 35mph but there

is no posted speed limit in either direction. Speed data collected atthe intersection indicates that vehicles have an 85th percentile speed

of 39 mph.

The evening or PM peak hour is the worst peak hour for traffic with approximately 1700 vehicles on Pleasant Street

(Route 5) and 600 vehicles on Conz Street. Traffic from Conz Street has to wait for a significant period of time

before finding an appropriate gap in Pleasant Street (Route 5) traffic. There are minimal pedestrian facilities at the

intersection and bicyclists have to share the road with motor vehicles due to the narrow shoulder. The goal of this

FDR is to analyze the existing traffic operations and recommend geometric changes that would not only improve

vehicular flow, but also provide suitable space for pedestrians and bicyclists.

2.2 Traffic Volumes

Nitsch Engineering coordinated a data collection effort at the study intersection, which included Turning

Movement Counts (TMC), Automatic Traffic Recorder (ATR) data, speed data, and vehicle classification data.

Precision Data Inc., our Subconsultant for data collection, performed the manual TMCs on Thursday, May 18,

2011. The TMCs were collected from 7:00 AM to 9:00 AM to capture the morning or AM peak hour of traffic

and from 4:00 PM to 6:00 PM to capture the evening or PM peak hour of traffic.

The ATR, speed, and vehicle classification data were collected for a 48-hour period from Wednesday, May 17,

to Thursday, May 18, 2011. The data were collected on Conz Street and the Pleasant Street northbound (NB)

and southbound (SB) approaches. Table 1 provides a summary of the traffic data collected.

View looking north on Pleasant Street atthe intersection.


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Table 1 Traffic Data Summary

Location

Peak Hour of Traffic

Volumes (TurningMovement Counts)

Automatic Traffic Recorder Data

85th

PercentileSpeed (mph)

Percentage ofHeavy Vehicles (%

of vehicles with 4or more axles)

Average

DailyTraffic

(vpd)

K-factor

1DirectionalDistribution

Pleasant Street(Route 5) &Conz Street

AM Peak: 8:00-9:00 AM - - - - -

PM Peak: 4:30-5:30 PM - - - - -

On Conz Street - 8,930 9% 54% EB 34 WB, 29 EB 0.9% WB, 0.8% EB

On PleasantStreet (Route 5)

North- 12,898 9% 53% NB 39 NB, 39 SB 0.5%NB, 0.5% SB

On PleasantStreet (Route 5)

South- 20,224 9% 50% NB 39 NB, 39 SB 0.8% NB, 0.7% SB

1 K-factor indicates the percentage of daily traffic flowing during the peak hour

As seen from Table 1, the peak hours of traffic at the intersection are from 8:00 to 9:00 AM and from 4:30 to

5:30 PM. Approximately 9% of the daily traffic flows during the peak hour which is within the anticipated range

of 7 to 11%. The directional distribution is approximately 50% in each direction on both Conz Street and

Pleasant Street (Route 5), indicating that the same route is used in both directions for morning and evening

commutes. Heavy vehicles with four or more axles comprised less than 2% of all traffic on both Conz Street

and Pleasant Street (Route 5).

Pedestrian and bicycle volumes at the intersection were minimal with five pedestrians observed during the

morning peak hour and five bicyclists observed during the evening peak hour.

Figure 2 shows the 2011 existing traffic volumes and Figure 3 shows the 2011 existing heavy vehicle volumes

at the intersection.


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2.3 Seasonal Adjustment and Background Growth

Seasonal Adjustment

MassDOT collects traffic volume data at various count stations across the state to study the monthly variation in

traffic on roadways that fall under MassDOT jurisdiction. Standard engineering practice is to compare collected

traffic volumes for a study with the nearest MassDOT station to establish variation from average traffic volumes.

Based on the 2007 weekday seasonal adjustment traffic data1, average traffic volumes on Rural Arterials in May

are higher than the average month. Additionally, we reviewed the following stations located in Northampton for

seasonal adjustment data:

Station 11 Routes 5 and 10, South of Hatfield T.L.

Station 2436 Route I-91 between Routes 5 and 9

Traffic volumes at these locations indicate that traffic volumes during the month of May are higher than the average

month by 4 7%. MassDOT recommends an adjustment factor of 0.91be multiplied to actual count data to reflect

average month traffic volumes. In order to remain conservative with the traffic analyses, we did not adjust the

traffic counts collected for this study.

Background Growth

MassDOT also records traffic volumes at stations over multiple years to establish the growth rate in the area

and to identify regional shifts in traffic. There are five MassDOT count stations in Northampton near the study

intersection; however, only one station had data from 2000 to 2009 that indicated traffic trends in the area:

Station 0011L, Rte. 5 and 10, 0.8 km south of Hatfield T.L. Based on the volumes at this station, there was a

1% annual decline in traffic volumes from 2000 to 2008, followed by an increase of approximately 4% from

2008 to 2009.

Additionally, comparing traffic volumes from 2011 to the counts collected for the PVPC Transportation Study at

the same intersection in 2005 also indicated a general decline. We anticipate that traffic growth in the area will

remain minor, if any, based on the negative trends observed in the past. To remain conservative, we used a

0.5% background growth annually to project 10-year design volumes.

In this FDR, the base year of traffic analyses is 2011, and therefore the 10-year design horizon is the year

2021.

1 Massachusetts Department of Transportation, 2007 Statewide Traffic Data Collection and madtcomp09.xls


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2.4 Crash Data

In order to identify potential safety deficiencies at an intersection, we reviewed crash data for the three latest

years for which data is available. MassDOT provided us with data from February 2008 to December 2010 atthe study intersection. The data was provided in the form of collision diagrams, crash records, and bar graphs

based on the type, roadway conditions, and driver characteristics, which are included in the Technical Appendix

of this report. Table 2 provides a summary of the crash data provided by MassDOT.

Table 2 Crash Data Summary

Location Year

Number

Type Percent Duringof Crashes

Total

Avg.

perYear

ANa

REb

HOc

Pedd

Othere

Peak Wet/Icy Dark/Night

Hours

Pleasant Street(Route 5) & ConzStreet

2008 14

11

6 6 - - 2 50% 7% 14%

2009 11 5 3 - - 3 9% 27% 27%

2010 8 3 4 - - 1 63% 50% 38%

Total 33 11 42% 40% - - 18%

a: AN Angle or cross-movement crash; b: RE Rear end crash; c: HO Head On Crash; d: Ped Crashes involving a pedestrian; e: Other sideswipe, singlevehicle crashes, and crashes where type is unreported.Source: MassDOT crashes from February 2008 to December 2010.

As seen from Table 2, the intersection experienced a total of 33 crashes from 2008 to 2010. Of these, 42%

were angle or cross-movement crashes and 40% were rear-end crashes. Angle crashes are the most

common type of crashes observed at unsignalized intersections and usually occur when drivers accept short

gaps in opposing traffic. Similarly, rear-end crashes occur owing to short driver reaction time and are

attributable to the unsignalized operation and high speeds at the intersection.

The severity of crashes was not indicated in the crash reports. A majority of the crashes occurred during peak

hours when heavy volumes are experienced. In general, the total number of crashes from 2008 to 2010

decreased by approximately 50%. This could be a result of altered driver behavior or a general reduction in

traffic volumes at the intersection.

We computed a crash rate at the intersection to compare it to District 2 and Statewide averages. Table 3

provides a comparison of the crash rate at this intersection with the 2008 District 2 and Statewide averages.

Table 3 Crash Rate

Intersection Crash Rate2

(acc/mev1)

District 2 Crash Rate3

(acc/mev)Statewide Crash Rate

3

(acc/mev)

Pleasant Street (Route 5) & ConzStreet

1.55

0.83 0.82

1: acc/mev Accidents per million entering vehicles; 2: Computed Value; 3: Source: MassDOT


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The crash rate at the intersection was 1.55 acc/mev, which is significantly higher than the District 2 average of

0.83 acc/mev and the Statewide average of 0.82 acc/mev at unsignalized intersections. The proposed

geometric design should be aimed at reducing the crash rate at the intersection without adversely affecting

traffic operations.

2.5 MUTCD Signal Warrants

The Manual on Uniform Traffic Control Devices (MUTCD) outlines eight warrants that are used to verify the

need for a traffic signal at an intersection. Even though meeting one or more warrants alone is not justification

for a signal, the warrants provide an indication of suitability of a traffic signal based on traffic volumes, crash

rates, pedestrian gaps, and traffic flow. For the intersection of Pleasant Street (Route 5) and Conz Street, we

applied the available 2011 traffic volumes to verify Warrants 1 (Eight-Hour Vehicular Volume), 2 (Four-Hour

Vehicular Volume), and 3 (Peak Hour). Table 4 provides a summary of the results.

Table 4 MUTCD Signal Warrants Summary

Warrant Met?

Warrant

#1A

Warrant

#1B

Warrant#1

(CombinedA&B)

Warrant

#2

Warrant

#3

Warrant#4

(PedestrianVolume)

Warrant#5

(SchoolCrossing)

Warrant #6(Coordinated

SignalSystem)

Warrant#7

(CrashExperience)

Warr#8

(RoadNetw

PleasantStreet(Route 5)& ConzStreet

Yes Yes Yes Yes Yes n/a n/a n/a n/a n/a

Source: MUTCD 2009, Section 4C Traffic Control Signal Needs Studies

As seen from Table 4, the intersection meets all of the warrants based on traffic volumes (Warrants 1 3).

Since the 2021 design year volumes would be higher than the 2011 traffic volumes based on the assumption of

0.5% annual increase, the warrants would continue to be met under 2021 conditions. Based on these results,

we analyzed a traffic signal at the intersection alongside other design alternatives.

2.6 Road Safety Audit

A Road Safety Audit (RSA) culminated our review of existing conditions, which we conducted in compliance

with MassDOTs guidelines for design improvements at the study intersection. The RSA was conducted on

Tuesday, June 21, 2011 and was attended by Nitsch Engineering engineers, MassDOT District 2 traffic and

safety officials, and City of Northampton traffic, safety, and emergency officials. A list of safety issues for this

intersection included the following:

1. Lack of traffic control at the intersection;

2. The acute angle at which Conz Street approaches the intersection;

3. Multiple driveway accesses within the intersection;

4. Lack of a specific northbound left turning lane onto Conz Street;

5. Lack of clear directional and warning signs; and

6. Lack of clear pavement markings and specifically the absence of crosswalks at the intersection.


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Nitsch Engineering prepared an RSA report that explains the above issues in greater detail as well as

proposing enhancements to address each of the issues. While most of the enhancements require short- to

medium-term implementation periods, we identified two enhancements as long-term enhancements involving

higher costs: realigning the Conz Street approach to improve the STOP control for vehicles turning onto

Pleasant Street southbound and reconstructing the intersection with a roundabout or traffic signal. All of thesafety enhancements would be undertaken as part of the intersection redesign and many of the short-term

enhancements may be initiated by MassDOT prior to completion of the design as resources allow.

3 PROPOSED IMPROVEMENTS

The goal of the current project is to design an optimal configuration of the intersection of Pleasant Street

(Route 5) and Conz Street that will improve traffic flow, maintain access and egress to properties surrounding

it, and provide accommodations for pedestrians and bicyclists. Proposed improvements to the geometric

layout would also involve cold plane and overlay of the existing pavement and modification of pavement

markings and signage. The following describes the improvements proposed as part of this project as theyrelate to intersection operation.

3.1 Geometric Layout

Nitsch Engineering has analyzed the following design alternatives to analyze future year traffic operations at

the study intersection:

1. Unsignalized Intersection This configuration would be similar to the existing conditions with modified lane

configuration, where Conz Street traffic would operate under a STOP control.

2. Signalized Intersection The intersection would be signalized with timing for all the approaches, including

the Gas Station/Car Wash approach.3. Roundabout Intersection The intersection would be redesigned as a roundabout. Traffic entering the

roundabout would yield to circulating traffic.

Unsignalized Intersection

The following are the geometry changes in the unsignalized configuration of the intersection when compared to the

existing and no-build conditions:

1. The proposed unsignalized configuration would consist of one left-turn and one through lane on the

Pleasant Street (Route 5) northbound approach and two general-purpose lanes on the Pleasant Street

(Route 5) southbound approach. The Conz Street eastbound approach would consist of one shared

left/through lane and one right-turn lane and the Gas Station/Car Wash driveway would consist of onegeneral-purpose lane in the westbound direction.

2. The Pleasant Street (Route 5) northbound left-turn lane and the Conz Street eastbound right-turn lane

would be storage lanes to increase capacity and minimize delays.

3. The Pleasant Street (Route 5) approaches would operate as the unrestricted movements and Conz Street

and the Gas Station/Car Wash Driveway would operate under STOP control.

4. The configuration would also consist of 4-foot shoulders on each side of Pleasant Street that could be used

as bicycle lanes and 5-foot wide sidewalks on all the approaches.


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Figure 4 Unsignalized & Signalized Intersection Configuration


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Roundabout Intersection

We reviewed four roundabout configurations as part of the FDR.

Alternative 1 has the following configuration:

Fifty-five-foot island diameter; Uniform 10-foot apron to enable truck turns;

One 15-foot circulating lane throughout the roundabout; and

Five-foot wide sidewalks along the outer edges of the roundabout.

Alternative 1 would have a uniform 105-foot inscribed diameter. This alternative would not require any land takings

and can be accommodated within the MassDOT highway layout lines; however, the biggest vehicle that this design

can accommodate is a WB-50 which is smaller than the WB-67 design vehicle. Traffic operations would improve

on Conz Street and the Gas Station/Car Wash driveway because left turning traffic would have to find gaps in only

one direction of traffic compared to gaps in two-way traffic under the existing conditions. The conflict between the

left-turns from Pleasant Street (Route 5) northbound and through vehicles on Pleasant Street (Route 5) southbound

would persist. Similarly, the conflicts between the right-turns from Conz Street eastbound and the through vehicleson the Pleasant Street (Route 5) southbound movement would persist, thus affecting traffic operations under this

alternative. Crosswalks for pedestrians would be provided across all approaches. Pedestrians would still be

required to wait for gaps in oncoming traffic as they do under current conditions; however, vehicle speeds would be

significantly reduced due to the geometric configuration of the roundabout. Figure 5 is a schematic illustration of

the general appearance of a one-lane roundabout.

Figure 5 Roundabout Alternative 1


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Fifty-five-foot island diameter;

Uniform 10-foot apron to enable truck turns;

One 15-foot circulating lane throughout the roundabout;

An additional 15-foot continuous lane from Conz Street to Pleasant Street (Route 5) southbound; and


Alternative 2 would have a 105-foot inscribed diameter on three sides of the roundabout with an additional 15-foot

lane to allow free movement of vehicles from Conz Street to Pleasant Street (Route 5) southbound. The additional

lane from Conz Street to Pleasant Street (Route 5) would require some land takings or permanent easements on

the Conz Street approach. Similar to Alternative 1, the largest vehicle that this design can accommodate would be

a WB-50. Traffic operations under Alternative 2 would be better than the existing conditions and Alternative 1

because of the continuous lane from Conz Street to Pleasant Street (Route 5). Similar to Alternative 1, pedestrians

would be provided with crosswalks at all approaches (not shown in schematic below). Figure 6 illustrates the

general characteristics of a modified one-lane roundabout.



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One 15-foot lane scored with cement concrete (or similar material) to discourage vehicular travel but

provide space for truck turns on the easterly and northerly sides of the island;

One 15-foot circulating lane throughout the roundabout;

An additional 15-foot continuous lane from Conz Street to Pleasant Street (Route 5) southbound; and


Alternative 3 would have a 135-foot inscribed diameter. This alternative would require land takings or permanent

easements of a small portion of the Gas Station/Car Wash driveway and the Conz Street approach. Compared to

existing conditions and Alternative 1 (single lane), this design would have better operations because of the

continuous lane from Conz Street to Pleasant Street (Route 5). Compared to Alternative 2, this design would be

able to accommodate the larger WB-67 truck turns. Pedestrians would be provided with crosswalks at all

approaches (not shown in schematic below).



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Two 15-foot circulating lanes throughout the roundabout;

Two entry lanes (with storage lanes) from Pleasant Street (Route 5) NB, Pleasant Street (Route 5) SB, andConz Street; and


Alternative 4 would have a uniform 135-foot inscribed diameter. This alternative would require land takings or

permanent easements of adjacent property near the intersection. Similar to Alternative 3, this design would be able

to accommodate a WB-67 truck. Due to the inclusion of two continuous travel lanes around the entire roundabout

and the double lane approaches on Pleasant Street and Conz Street, Alternative 4 would have the best traffic

operations among the alternatives considered but would also require the most space outside of the MassDOT

highway layout lines. Pedestrians would be provided with crosswalks at all approaches, but generally would require

more time to cross the intersection compared to the other alternatives due to the increased pavement width at each

approach.

The following section provides a more detailed and quantitative evaluation of the alternatives using various metrics

as the basis for comparison. See Table 8 for a summary of the level of service, volume to capacity ratio, and delay

time associated with the six alternatives described above.


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3.2 Level of Service Criteria

Level of Service (LOS) is a qualitative measure describing operational conditions within a traffic stream. Six levels

of LOS are used to describe the quality of traffic flow for any type of facility controls with LOS-A representing the

best operating conditions and LOS-F representing the worst operating conditions. Levels of service for signalized

intersections are calculated using the operational analysis methodology of the Highway Capacity Manual (HCM).

The methodology for signalized intersections assesses the effects of signal type, timing, phasing, and progression,

vehicle mix, and geometrics on average control delay. Control delay includes initial deceleration delay, queue

move-up time, stopped delay, and final acceleration delay. Table 5 summarizes the relationship between level of

service and average control delay for signalized and unsignalized intersections.

Table 5 Level of Service for Intersections

3.3 Capacity Analysis Results

We performed traffic analyses to evaluate traffic operations under existing and future year conditions. A summaryof the capacity analysis results depicting volume to capacity (v/c) ratio, vehicle delay, level-of-service (LOS), and

vehicle queue is provided in Tables 6 8. Table 6 summarizes the intersection operations under current 2010

traffic volumes for both the weekday AM and PM peak hours. The analysis worksheets are provided in the

Technical Appendix of this report.

Table 6 Level of Service Summary 2011 Existing Conditions

NAME MOVEMENT

2011 AM PEAK HOUR 2011 PM PEAK HOUR

V/C1 DELAY2 LOS3 95th Q4 V/C1 DELAY2 LOS3 95th Q4

Pleasant Pleasant St. (Route 5) NB L 0.32 9.6 A 34 0.61 16.1 C 105

Street (Route 5) Pleasant St. (Route 5) SB LTR 0.04 1.3 A 3 0.04 1.1 A 3

at Conz Street & Conz St. EB LT 0.71 211.5 F 65 >1.0 ++ F ++

Gas Station/Car Conz St. EB R 0.84 32.7 D 226 >1.0 ++ F ++

Wash Driveway Gas Station/Car Wash Driveway WB LTR >1.0 ++ F ++ >1.0 ++ F ++

Intersection ++ ++

1Volume to Capacity Ratio;

2Vehicle Delay, measured in seconds;

3Level Of Service;

495

thPercentile Queue; ++: very high values; L=Left; T=Through; R=Right

Under the existing conditions, we modeled the intersection with additional turn lanes in the eastbound and

northbound directions because site observations indicated that drivers used the wide approaches as two lanes. As

seen in Table 6, there are no queues on the Pleasant Street (Route 5) approaches during the morning or evening

Signalized Intersections Unsignalized Intersections

Level of

Service1

Stopped Delay per Vehicle1

(Seconds)

Level of

Service1

Stopped Delay per Vehicle1

(Seconds)

A 0 to 10 A 0 to 10

B >10 to 20 B >10 to 15

C >20 to 35 C >15 to 25

D >35 to 55 D >25 to 35

E >55 to 80 E >35 to 50

F Over 80 F Over 501 Reference: 2000 Highway Capacity Manual, TRB


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peak hours; however, vehicles turning left from the Conz Street approach and the Gas Station/Car Wash driveway

experience long queues and delays during both the morning and evening peak hours.

Nitsch Engineering has performed the traffic analysis of the study intersections for the future year No-Build

condition. The No-Build condition represents the traffic operation at the intersections with volumes projected to2021 based on a 0.5% per year background growth rate. Under the 2021 No-Build condition, the intersection would

remain unsignalized. Table 7 summarizes the intersection alternatives under the 2021 No-Build condition. The

analysis worksheets are provided in the Technical Appendix of this report.

Table 7 Level of Service Summary 2021 No Build

NAME MOVEMENT



Pleasant Pleasant St. (Route 5) NB L 0.32 9.7 A 35 0.56 14.6 B 88

Street (Route 5) Pleasant St. (Route 5) SB LTR 0.05 1.4 A 4 0.03 0.8 B 2

at Conz Street & Conz St. EB LT 0.65 210.5 F 57 >1.0 ++ F ++

Gas Station/Car Conz St. EB R 0.84 32.6 D 226 >1.0 ++ F ++Wash Driveway Gas Station/Car Wash Driveway WB LTR >1.0 ++ F ++ >1.0 ++ F ++

Intersection ++ ++



3Level Of Service;

495

thPercentile Queue; ++: very high values; L=Left; T=Through; R=Right

As seen in Table 7, the intersection would operate at similar LOS and with similar delays under the 2021 No-Build

condition, when compared to the 2011 existing conditions. The Conz Street approach and the Gas Station/Car

Wash driveway would continue to have significant queuing during the peak hours, especially the PM peak hour, if

no geometric or operational improvements are made at the intersection.

Nitsch Engineering analyzed the three design alternatives discussed previously, a modified unsignalized

intersection, a signalized intersection, and a roundabout (four alternatives), under the 2021 Build condition at theintersection, to review traffic operations and present the pros and cons of each alternative. Table 8 summarizes the

intersection alternatives under the 2021 Build condition. The analysis worksheets are provided in the Technical

Appendix of this report.


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Table 8 Level of Service Summary 2021 Build

NAME MOVEMENT



Pleasant Pleasant St. (Route 5) NB L 0.32 9.7 A 36 0.56 14.6 B 89

Street (Route 5) Pleasant St. (Route 5) SB LTR 0.05 2.0 A 4 0.03 0.9 A 2

at Conz Street & Conz St. EB R 0.69 27.5 D 142 >1.0 111.2 F 1081

Gas Station/Car Gas Station/Car Wash Driveway WB LTR >1.0 ++ F ++ >1.0 ++ F ++

Wash Driveway Intersection ++ ++

(Unsignalized)

Pleasant Pleasant St. (Route 5) NB L 0.66 19.9 B 394 0.80 35.1 D 605

Street (Route 5) Pleasant St. (Route 5) NB TR 0.60 7.7 B 584 0.52 6.0 A 512

at Conz Street & Pleasant St. (Route 5) SB LTR 0.71 24.8 C 291 0.76 29.9 C 473

Gas Station/Car Conz St. EB LT 0.15 24.6 C 33 0.12 38.2 D 36

Wash Driveway Conz St. EB R 0.34 11.4 B 36 0.51 19.5 B 76

(Signalized)Gas Station/Car Wash Driveway WB LTR 0.46 27.4 C 77 0.44 41.3 D 94Intersection 0.59 15.4 B 0.75 22.7 C

Pleasant Pleasant St. (Route 5) NB LTR 0.84 9.9 B 506 0.85 9.2 B 595

Street (Route 5) Pleasant St. (Route 5) SB LTR 0.58 10.5 B 122 >1.0 45.8 D 850

at Conz Street & Conz St. EB LTR 0.74 10.8 B 210 >1.0 157 F 1600+

Gas Station/Car Gas Station/Car Wash Driveway WB LTR 0.26 14.1 B 47 0.27 15.8 B 50

Wash Driveway Intersection - -

(Roundabout,Alternative 1)


Street (Route 5) Pleasant St. (Route 5) SB LTR 0.56 10.4 B 113 >1.0 37.5 D 741

at Conz Street & Conz St. EB LT 0.03 11.0 B 4 0.04 12.5 B 6

Gas Station/CarConz St. EB R 0.34 3.2 A 0 0.41 3.2 A 0Wash Driveway Gas Station/Car Wash Driveway WB LTR 0.23 14.1 B 39 0.24 15.9 B 42

(Roundabout,Alternative 2) Intersection - -

Pleasant Pleasant St. (Route 5) NB LTR 0.73 12 B 318 0.73 8.7 B 345

Street (Route 5) Pleasant St. (Route 5) SB LTR 0.52 9.8 B 99 0.94 23.3 C 518

at Conz Street & Conz St. EB LT 0.03 10.8 B 4 0.04 12.3 B 6

Gas Station/Car Conz St. EB R 0.34 3.0 A 0 0.40 2.9 A 0

Wash Driveway Gas Station/Car Wash Driveway WB LTR 0.20 13.5 B 36 0.22 15.1 B 39

(Roundabout,Alternative 3) Intersection - -


Street (Route 5) Pleasant St. (Route 5) SB LTR 0.25 8.5 B 30 0.45 9.2 B 70

at Conz Street & Conz St. EB LTR 0.30 5.2 B 33 0.43 6.3 B 58

Gas Station/Car Gas Station/Car Wash Driveway WB LTR 0.16 10.2 B 17 0.16 9.8 B 17

Wash Driveway Intersection - -

(Roundabout,Alternative 4)



3Level Of Service;

495

thPercentile Queue; ++: very high values; L=Left; T=Through;R=Right

As seen in Table 8, the intersection of Conz Street and Pleasant Street (Route 5) would operate at acceptable

levels of service and queues under the signalized intersection alternative and the roundabout Alternatives 3 and 4.


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Under these Alternatives, all approaches would operate at LOS D or better, which is representative of moderate

traffic conditions per MassDOT standards.

The modified unsignalized intersection would continue to operate at LOS F with shorter queues when compared to

the No-Build condition, because providing an auxiliary through lane on Pleasant Street (Route 5) SB and storageturning lanes on Pleasant Street (Route 5) NB and Conz Street EB approaches increases capacity. The roundabout

Alternatives 1 and 2 would operate at better levels of service compared to the 2021 No-Build condition, but would

continue to experience long queues, especially during the PM peak hour. A comparison of the alternatives in terms

of initial cost, operations, and maintenance costs are shown in Table 9.

Table 9 Evaluation of Alternatives

Capital Cost

Pedestrian &Bicycle

Accommodations Energy UseTraffic

Operations Maintenance Cost

Modified STOP control

Traffic Signal

Roundabout Alternative 1




Low Medium High

It must be noted that the summary of traffic operations at the signalized intersection, as shown in Table 8 and Table

9, are reflective of cycles when the exclusive pedestrian phase is activated and the vehicular phases are stopped toprocess the pedestrian phase. We anticipate that the traffic operations would be better than projected for a

majority of the times when the pedestrian phase is not activated.

The analyses output for the 2021 Build conditions are included in the Technical Appendix.

3.4 Environmental Impacts

Based on a review of the MassGIS database and preliminary discussions with the Northampton Conservation

Commission staff, it appears that there are no environmental resource areas within 200 feet of the project

location. The alternatives discussed within this report should not require the filing of a Notice of Intent with the

Northampton Conservation Commission.

The project is located approximately 500 feet north of a flood control levee which is partially controlled by the

Army Corps of Engineers. Discussions with the Corps have concluded that official Corps review and approval

is most likely not warranted given the limited scope of the project. Nitsch Engineering does not anticipate that

any of the design alternatives discussed above will impact the existing levee structure; however, the Corps has

requested the opportunity to informally review the 25% design plans when complete.


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4 CONCLUSIONS

The intersection of Pleasant Street (Route 5) and Conz Street experiences substandard traffic operations given

the heavy volumes on Pleasant Street (Route 5) and Conz Street. Other issues include confusing access to

the Gas Station/Car Wash driveway, a very high crash rate when compared to the statewide and District 2averages, and limited pedestrian and bicycle accommodations. Nitsch Engineering identified the deficiencies

at the intersection through an RSA and developed six alternatives that would provide operational and geometric

improvements over the existing conditions.

The six alternatives reviewed include a modified UnsignalizedIntersection, a Signalized Intersection, and four

Roundabout Alternativeswith varying diameters and entry and exit lane configurations. Both the City of

Northampton and MassDOT District 2 staff have indicated that the preferred design should be capable of

accommodating a WB-67 vehicle and therefore Roundabout Alternatives 1 and 2would be eliminated.

Roundabout Alternative 4provides the best operational characteristics but would require significant right-of-way

acquisition and impacts to adjacent abutters and would likely be the most costly to construct. The Unsignalized

Intersectionis the least costly and has no impact to right-of-way but does not adequately address theoperational deficiencies of the intersection. Therefore, from the six alternatives, Nitsch Engineering concludes

that either the Signalized Intersectionor Roundabout Alternative 3would be the most desirable design.


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Section

Number

5 TECHNICAL APPENDIX

A-1 2011 Turning Movement Counts

A-2 Seasonal Adjustment Data and Background Growth Data

A-3 Crash Rate Data and Worksheets

A-4 Signal Warrant Analysis

A-5 Capacity Analysis of Existing Year 2011

A-6 Capacity Analysis of Design Year 2021 No Build & Build Alternatives

Documents

11-7 Conz & Pleasant Functional Design Report Nitsch Engineering