Highway Design Class

CTC 440

Introductions

Students Me

Class Basics

www.sunyit.edu/~barans/ Syllabus Tentative Schedule Lectures Labs Grades (PIN #’s)

Ch 5 of HDM: Basic Design Designing a section of highway is

similar to designing a house Lots of little decisions along the way

that impact the end product

Some Basic Elements Capacity/Level of Service Accident Analysis Terrain Data Requirements Right-of-Way Construction Cost Estimates Design Elements Design Considerations Intersections at Grade

Capacity / Level of Service Capacity analysis is used to estimate

the traffic-carrying ability of existing and proposed traffic

(LOS) is a qualitative measure used to describe the operational conditions within a traffic stream – driver’s viewpoint A (best) F (failure) LOS C – desirable; LOS D acceptable

Accident Analysis – Identify problems and incorporate countermeasures

Collect data Determine accident rate and compare to

statewide avg. Identify locational clusters Identify nonstandard or nonconforming

features PIL/PII (priority investigation

list/intersection) Utility Pole “bad actors”

Terrain Data RequirementsObtained via photogrammetry &/or field survey

Base Mapping (horizontal) Edge of pavements, shoulders, sidewalks Buildings, fences, trees, tree lines Rock outcrops Utilities-lines, valves, manholes Streams, creeks

Topography (vertical) DTM – digital terrain models Used for contours and cut cross-sections

Right of WayAmt. of land needed

ARM-abstract request map ROW plan Power of eminent domain Types

Fee, w/ access or w/o access PE (permanent easement) TE (temporary easement) TO (temporary occupancy, <$2500, minor

grading/ditching) Entrance, approach, or driveway work release (no

compensation General work release (no compensation)

Construction Cost EstimatesPrepared throughout project life

Ballpark (+/-50%) Preliminary (+/-20%)

PEP (preliminary estimate program) or MEANS Detailed (+/-5%)

PES (preliminary estimating system) or MEANS Economic Analysis

Bridge rehab vs replacement Bridge abandonment vs preservation Pavt. Rehab options Accident reduction treatments Mobility betterment

Design Elements Design Vehicle Sight Distance Horizontal and Vertical Alignment Superelevation Climbing or emergency escape lanes Clear Zone Vertical and Horizontal Clearance Parking lanes, driveways Lane drops, medians Frontage roads HOV lanes, bus stops/turnouts/turnarounds

Design Considerations Joint Use of Highway

(peds/bikes/utilities/transit) Driver Expectancy Geometric Considerations Noise Abatement Increase capacity w/o addl. Lanes

ITS Ramp Metering Reversible-flow lanes Shoulders as traffic lanes HOV priority treatment

Intersections at Grade Use HCM to determine LOS/Capacity Intersection Geometries

Angle (skew < 30 deg) Channelization/pavt width/radii

Other Considerations Sight distance/access control signalization

Medians Flush or Raised Median Openings

Highway Stuff

2007 Minneapolis Bridge Collapse Bolivia Road