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 Requirements Obtained 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 Way Amt. 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 Estimates Prepared 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