Ramp Metering Feasibility Study Alf Badgett, PE

October 18, 2017

Transportation

What is a Ramp Meter? Ramp meters are traffic

signals installed on freeway on-ramps to control the frequency at which vehicles enter the main freeway

The ramp meters monitor the flow on both the freeway and the on-ramp

Manages the flow onto the freeway from the on-ramp by briefly stopping vehicles until there is a ‘safe gap’ for the on-ramp traffic to enter into safely

Transportation

Ramp Metering Mitigates congestion by managing the rate of traffic entering the

freeway from the on-ramp Breaks up traffic platoons on ramps into smaller ‘platoons’ that can

more easily merge with the heavily congested freeway traffic. Improves the situation by:

o Reducing the flow rate of vehicles onto the mainline

o Reducing the platoon size to make merging easier

Transportation

Study Area Study area includes all of the entrance ramps for

Interstate routes in the Metrolina area (Cabarrus, Gaston, Iredell, and Mecklenburg counties)

Transportation

Partners Partners

o NCDOT Transportation Mobility and Safety o NCDOT Division 10 (Cabarrus and Mecklenburg Counties) o NCDOT Division 12 (Gaston and Iredell Counties) o Federal Highway Administration (FHWA) o Charlotte Regional Transportation Planning Organization (CRTPO) o City of Charlotte Department of Transportation (CDOT) o Gaston-Cleveland-Lincolnton Metropolitan Planning Organization

(GCLMPO) o City of Gastonia o Cabarrus-Rowan Metropolitan Planning Organization (CRMPO) o City of Concord o Atkins

Transportation

Project Tasks Data Collection – utilize, as much as possible, existing data

sources, including traffic data, crash data, and geometric data. Screening Analysis – perform high-level analysis of the sites

to filter out those locations not meeting the criteria for ramp metering. As the analysis proceeds, a master list of all sites will be maintained with the critical data and record of the decision making process.

Detailed Analysis – perform an in-depth analysis of the sites that have potential to meet the criteria for ramp metering. The analysis will consider the potential impacts upon the crossing streets and the operations of the adjacent traffic signals.

National Research - research and review the state of the art technology, site selection criteria, implementation, and design standards.

Legal and Regulatory Review - research, review and summarize the state regulations and statutes concerning the operation and enforcement of ramp meters.

Transportation

Project Tasks Design Criteria - develop typical design prototypes to address typical

solutions for the candidate ramp metering sites. Cost Estimates - develop typical planning-level quantities suitable for TIP

budget level cost estimates. Performance Measures – develop performance measures to evaluate and

rank the projects in the Implementation Plan. Implementation Plan - evaluate and rank the preferred alternative for each

site based upon the performance measures.

Transportation

Site Selections There were 241 sites that were included as potential ramp

meter locations: o Cabarrus - 15 o Gaston - 15 o Iredell - 23 o Mecklenburg – 188

After a site evaluation and detailed analysis, the list was screened down to 50 sites: o Cabarrus - 0 o Gaston - 6 o Iredell - 4 o Mecklenburg – 40

Transportation

Site Selection Criteria Amount of congestion on the on-ramp

o INRIX Vehicle Probe Data Site evaluation

o General location data o Sight distance Issues o Ramp gradient o Pavement condition o Guardrail o Shoulder availability o Potential to widen/alter ramp layout o CCTV coverage o ITS communications availability o Ramp geometrics o Vegetation

Crash Data Traffic Signal Data

Transportation

Site Selection Criteria The following types of site were ruled out following the geometric

and congestion analysis: o Sites where there was no significant congestion (reduced the number

to 112 sites)

o Freeway to Freeway (F2F) sites experiencing significant congestion (reduced the number to 90 sites)

o Sites upstream of Freeway to Freeway (F2F) primary sites (reduced the number to 76 sites)

o Sites at the extreme back of congestion (reduced the number to 68 sites)

o Sites where the bottleneck data could have been affected by other active construction projects (reduced the number to 60 sites)

o Sites which do not pass the geometric analysis, e.g. where the ramp cannot be extended/widened to provide sufficient acceleration distance (reduced the number to 50 sites)

Transportation

Site Selection Criteria Sites were categorized as Feasible, Review in Future, and Not Feasible based on an analysis of the following:

Congestion characteristics, and location in relation to other ramp metering sites which are being taken forward for implementation

Traffic volume analysis: o Ramp volumes: 300-1,200 vph acceptable, 400-900 vph ideal o Ramp volume / downstream volume: 5-50% acceptable, 10-30%

ideal

Geometric considerations: o Ramp type, e.g. collector distributor road, complex freeway-to -

freeway o Storage capacity / scope for widening o Visibility / curvature of the ramp

After performing detailed analysis on each site, the list of 50 potential sites was reduced to 38 sites for final evaluation.

Transportation

Suitable Sites Log FROM Cross Street TO

Freeway Freeway Direction

Exit County Ramp Type

Recommendation

32 S Main St I-85 NB 22 Gaston Direct Feasible

34 McAdenville Rd I-85 NB 23 Gaston Direct Feasible

35 Belmont-Mt. Holly Rd I-85 SB 26 Gaston Direct Feasible

93 Westinghouse Blvd I-77 SB 1A Mecklenburg Direct Feasible

101 Arrowood Rd I-77 NB 3 Mecklenburg Direct Feasible

102 Nations Ford Rd I-77 SB 4 Mecklenburg Direct Feasible

103 Nations Ford Rd I-77 NB 4 Mecklenburg Direct Feasible

105 Tyvola Rd I-77 NB 5 Mecklenburg Direct Feasible

111 Remount Rd I-77 SB 8 Mecklenburg Direct Feasible

129* I-85 SB I-77 NB 13 Mecklenburg F2F Feasible

140 Gilead Rd I-77 NB 23 Mecklenburg Direct Feasible

Transportation 13

Log FROM Cross Street TO Freeway

Freeway Direction

Exit County Ramp Type

Recommendation

143 NC 73

(Sam Furr Rd) I-77 NB 25 Mecklenburg Direct Feasible

145 US 21

(Catawba Ave) I-77 NB 28 Mecklenburg Direct Feasible

146 Goodrum Rd / Griffith St I-77 SB 30 Mecklenburg Direct Feasible

147 Goodrum Rd / Griffith St I-77 NB 30 Mecklenburg Direct Feasible

64 Graham St I-85 SB 40 Mecklenburg Loop Feasible

67 Sugar Creek Rd I-85 NB 41 Mecklenburg Direct Feasible

72 Harris Blvd I-85 SB 45 Mecklenburg Direct Feasible

75 Mallard Creek Rd I-85 NB 46 Mecklenburg Direct Feasible

177 Steele Creek Rd I-485 Inner 4 Mecklenburg Loop Feasible

179 Steele Creek Rd I-485 Inner 4 Mecklenburg Direct Feasible

181 West Blvd I-485 Inner 6 Mecklenburg Direct Feasible

Suitable Sites

Transportation 14

Log FROM Cross Street TO Freeway

Freeway Direction

Exit County Ramp Type

Recommendation

230 NC 16

(Providence Rd) I-485 Outer 57 Mecklenburg Direct Feasible

231 NC 16

(Providence Rd) I-485 Inner 57 Mecklenburg Loop Feasible

232 NC 16

(Providence Rd) I-485 Outer 57 Mecklenburg Loop Feasible

233 NC 16

(Providence Rd) I-485 Inner 57 Mecklenburg Direct Feasible

234 Rea Rd I-485 Outer 59 Mecklenburg Direct Feasible

236 Rea Rd I-485 Inner 59 Mecklenburg Loop Feasible

237 Rea Rd I-485 Inner 59 Mecklenburg Direct Feasible

239 US 521

(Johnston Rd) I-485 Outer 61 Mecklenburg Loop Feasible

Suitable Sites

Transportation 15

Log FROM Cross Street TO Freeway

Freeway Direction

Exit County Ramp Type

Recommendation

Review in Future

30 Cox Rd I-85 NB 21 Gaston Direct Review in Future

37 Beatty Dr /

Park St I-85 SB 27 Gaston Direct Review in Future

104 Tyvola Rd I-77 SB 5 Mecklenburg Direct Review in Future

175 Arrowood Rd I-485 Inner 3 Mecklenburg Direct Review in Future

182 US 74 / US 29

(Wilkinson Blvd) I-485 Outer 9 Mecklenburg Review in Future

229 E John St I-485 Inner 52 Mecklenburg Direct Review in Future

Not Feasible

97* I-485 I-77 SB 1B Mecklenburg F2F Not Feasible

250 Briar Creek Rd US 74 WB 244 Mecklenburg Direct Not Feasible

* Freeway-to-Freeway site

Suitable Sites

Transportation

Costs Four types of costs associated with the implementation and operation

of a ramp metering site: o Implementation or Construction Costs:

Design costs Construction costs

Ramp Meter Equipment Signing Pavement Markings Temporary Traffic Control Drainage Improvements Guardrail Roadway Resurfacing or Widening Related Earthwork Controller firmware

o Annual Maintenance and Operation Costs: Maintenance Operations Annual Software Support

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Transportation

Costs o Equipment Replacement Costs: *

Controllers Servers Communications Hardware System Software/Firmware LED Signal Heads Design costs Construction costs

* Since the replacement period is typically ten years then replacement costs were not

considered in this analysis since the analysis covers a ten-year period.

o Program Costs Fixed Costs Central Control Software Procurement and Integration Software Drivers Training Servers Miscellaneous central communications hardware

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Transportation

Final Filtering Criteria

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The final 38 sites were evaluated and 17 sites were eliminated based on the criteria below:

Sites affected by STIP projects

F2F sites Site 75, due to current the Congestion Management study

Sites categorized as ‘Review in Future’

o The effectiveness of these sites is less certain and will need to be reassessed following the implementation of other ramp metering sites within the same corridors.

Sites which are not expected to pay for themselves within five years of construction (i.e. sites with a five-year BCR of less than 1)

o These sites are not deemed economically suitable for implementation.

There are 21 sites being recommended to move forward for implementation.

Transportation

Final Recommended Sites

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Log FROM Cross Street TO Freeway

Freeway Direction

Exit County

32 S Main St I-85 NB 22 Gaston

34 McAdenville Rd I-85 NB 23 Gaston

35 Belmont-Mt. Holly Rd I-85 SB 26 Gaston

93 Westinghouse Blvd I-77 SB 1A Mecklenburg

101 Arrowood Rd I-77 NB 3 Mecklenburg

102 Nations Ford Rd I-77 SB 4 Mecklenburg

103 Nations Ford Rd I-77 NB 4 Mecklenburg

105 Tyvola Rd I-77 NB 5 Mecklenburg

111 Remount Rd I-77 SB 8 Mecklenburg

145 US 21 (Catawba Ave) I-77 NB 28 Mecklenburg

146 Goodrum Rd / Griffith St I-77 SB 30 Mecklenburg

Transportation

Final Recommended Sites

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Log FROM Cross Street TO Freeway

Freeway Direction

Exit County

147 Goodrum Rd / Griffith St I-77 NB 30 Mecklenburg

64 Graham St I-85 SB 40 Mecklenburg

67 Sugar Creek Rd I-85 NB 41 Mecklenburg

177 Steele Creek Rd I-485 Inner 4 Mecklenburg

179 Steele Creek Rd I-485 Inner 4 Mecklenburg

181 West Blvd I-485 Inner 6 Mecklenburg

234 Rea Rd I-485 Outer 59 Mecklenburg

236 Rea Rd I-485 Inner 59 Mecklenburg

237 Rea Rd I-485 Inner 59 Mecklenburg

239 US 521 (Johnston Rd) I-485 Outer 61 Mecklenburg

Transportation

Group 1 - I-85 South (Gaston County)

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Log Freeway Cross Street Exit Direction

032 I-85 S Main St 22 NB

034 I-85 McAdenville

Rd 23 NB

035 I-85 Belmont-Mt.

Holly Rd 26 SB

Transportation 23

Group 2 - I-85 North Mecklenburg County

Log Freeway Cross Street Exit Direction

067 I-85 Sugar Creek

Rd 41 NB

064 I-85 Graham

St 40 SB

Transportation 24

Group 3 – I-77 South

Log Freeway Cross Street Exit Direction

101 I-77 Arrowood

Rd 3 NB

103 I-77 Nations Ford Rd

4 NB

105 I-77 Tyvola Rd 5 NB

093 I-77 Westing-

house Blvd

1A SB

102 I-77 Nations Ford Rd

4 SB

111 I-77 Remount

Rd 8 SB

Transportation 25

Group 4 – I-77 North

Log Freeway Cross Street Exit Direction

145 I-77 US 21

(Catawba Ave) 28 NB

147 I-77 Goodrum Rd /

Griffith St 30 NB

146 I-77 Goodrum Rd /

Griffith St 30 SB

Transportation 26

Group 5 – I-485 Southwest

Log Freeway Cross Street Exit Direction 177 I-485 Steele Creek Rd 4 Inner 179 I-485 Steele Creek Rd 4 Inner 181 I-485 West Blvd 6 Inner

Transportation 27

Group 6 – I-485 Southeast

Log Freeway Cross Street Exit Direction 236 I-485 Rea Rd 59 Inner 237 I-485 Rea Rd 59 Inner 234 I-485 Rea Rd 59 Outer

239 I-485 US 521

(Johnston Rd) 61 Outer

Transportation

Recommendation for Deployment

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Ramp Metering Feasibility Study

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Questions?