Dr. Naveed Anwar Executive Director, AIT Consulting Affiliated Faculty, Structural Engineering Director, ACECOMS
Overview Highway Functions and Classifications Highway Design Components Design Control and Criteria Highway Cross Section Elements 2
Functional Classification The process by which streets and highways are grouped into classes, or systems, according to the character of traffic service that they are intended to provide 4
Functional Classification Streets and highways classification Orderly grouping roads based on service Assist in geometric design features In accordance with operational needs Establishes hierarchy of roads Efficient and safe if road serve their purpose Assessment of operating conditions Comparison between actual and intended purpose Chance to sort data based on type of road Collision data not yet available Three functional classifications: arterials Collector local roads 5
Roadway Functional Classes Determined by characteristics: function access density traffic demands trip length expected speed 6
Highway Function Classification Toll 7
Non Access Control Highway 8
Partial Access Control Highway At-grade U-turn Frontage Road Main Road Frontage Road Separator Median Main Road Separator 9
Full Access Control Highway Service Road Service Road Fence Fence Main Motorway 10
Highway Design Components Study of Route Selection Geometric Design Pavement Design Structural Design Planning, designate traffic Horizontal alignment design Flexible pavements Bridges, culverts Topographic survey and physical data Grade separate structures for interchanges Environment and social impact Vertical alignment design Rigid pavements Elevated roadways, viaducts Highway engineering preliminary design of routes Tunnels, underpass Evaluation and comparison Cross section design Highway materials Buildings, toll plaza, rest area, bus stop shelter, pedestrian walkway etc. 12
Highway Design Components Drainage Design Road Safety Design Intersections Types of highway drainage Evaluation and computation of rainfall intensity, catchment area, run-off, hydrology & hydraulic design, selection of drainage structures Erosion control design Road side safety design Traffic signs, marking, delineators Traffic signals Street lighting Other measures for road safety At grade intersections Basic types Capacity evaluation & configuration Geometric design of components Traffic controls design Drainage design Safety design Grade separate intersection, interchanges Basic types Capacity and level of service Design criteria Geometric design of components Traffic control & safety design 13
Highway Design Process 14
Design Control and Criteria Traffic Characteristics Volume ADT, Peak hour Capacity Design volume, service flow rate, distribution Level of service Density, speed, V/C congestion Design Vehicles Classes of vehicles Passenger car, trucks, buses Vehicle performance and characteristics Turning radius, pavement width, acceleration, deceleration, climbing on gradient, weight, and braking 15
Design Control and Criteria Driver Performance Perception and reaction Sight distance, stopping, passing Signs, intersection Traffic control devices Laws and regulations Speed Design speed Horizontal alignment, vertical alignment, intersection Operating speed Running speed Access Control Pedestrian and other Facilities 16
General Guidelines for Cross Section Design The design of the cross section shall be conform to design traffic volumes and the level of service of the road to obtain the capacity, efficiency, safety and sufficient functions at present time as well as future time Cross section should be designed according to highway classes such as freeway, arterial, collector and local roads etc. as recommended in the design standards The design of the cross section shall consider the type of highway construction projects such as the new construction of highway, widening project, the rehabilitation project, the surface overlay, intersection or interchange ramps etc. The design of the cross section shall conform to the types of terrain such as flat terrain, on soft ground foundation, hilly, mountainous, urban area, rural area etc. 18
General Guidelines for Cross Section Design The design of the cross section carried out on some specific purposes of serviceability such as road to industrial estates with heavy truck volumes, military services, 2-lane road with passing lane or climbing lane, reversible lane, road with bicycle lane, scenic road (tourism), road in preserved area etc. The design of cross section should always consider as stage construction, 1 st stage construction at present time, future stage widening and ultimate stage design 19
OVERPASS UNDERPASS BRIDGE Barrier Fence 3.00 Shoul der 3 @ 3.60 m. Carriage way 3 @ 3.60 m. Carriage way 3.00 Shoul der Barrier Fence Service Roads Motorway Main Road Service Roads 20
Typical Cross Section of Multi Lane Rural Road 21
Typical Cross Section: Multilane Raised Median Highway 22
Typical Cross Section: Multilane Raised Median Highway 23
Typical Cross Section: Multilane Depressed Median Highway 24
Typical Cross Section: Multilane Depressed Median Highway 25
Typical Cross Section: Multilane Highway with Median Barrier 26
Typical Cross Section: Multilane Highway with Median Barrier 27
Typical Cross Section: Multilane Highway with Paint Strip Median (Flush Median) 28
Comparison: Types of Median 29
Multilane Highway with Frontage Road Frontage Road Frontage Road Separator Median Separator Main Road Main Road 30
Typical Cross Section: Multilane Urban Highway Typical Cross Section for Ultimate Design 31