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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
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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