other important designcontrols and criteria
Vehicles
Drivers and Pedestrians
Traffic
These are the selected vehicles with representative weight, dimensions and operating characteristics used to establish highway design controls for accommodating vehicles of designated classes.
Design vehicles
_____________ and ___________ of vehicles are often the critical parameters in determining highway design for intersections, freeway ramps, climbing or passing lanes and turnout bays for buses.
Acceleration and deceleration rates
Designer should consider ____________ in their geometric design.
driver performance
This is critical in guiding designers to understand driver’s needs when they drive on roads.
transportation-based human factor theory
Each driver when driving will handle three types of information:
Control, Guidance, and Navigation
This indicates the need for the improvement and directly affect the geometric design features, such as number of lanes, widths, alignments and grades.
Traffic volume
This is the number of vehicles per unit length of roadway and is used as the measure of quality of traffic service for freeways and multilane highways.
Density
Is the maximum hourly rate at which persons or vehicles can reasonably be expected to traverse a point during a given time under prevailing roadway and traffic conditions.
Capacity
Highway Capacity Analysis is often done using Highway Capacity Manual (HCM) for three purposes:
a) Transportation planning studies
b) Highway design
c) Traffic operational analysis
used to assess the adequacy or sufficient of an existing facility or a highway network to serve current traffic
Transportation planning studies
used to select highway type and number of lanes
Highway design
used to identify bottleneck locations
Traffic operational analysis
Traffic volume projected to use a particular facility during the design year.
Design Volume
Maximum hourly rate of traffic that a highway with particular design features would be able to serve without the degree of congestion failing below a pre-selected level.
Design Service Flow Rate
Measure of Congestion
Uninterrupted Traffic Flow
Interrupted Traffic Flow
uses density as the measure for the degree of congestion
Uninterrupted Traffic Flow
uses average stopped time delay-signalized intersection
Interrupted Traffic Flow
Government Agencies Related to Highways and National Roads
Department of Public Works and Highways (DPWH)
Department of Transportation (DOTr)
Land Transportation Office (LTO)
Toll Regulatory Board (TRB)
Local Government Units (LGUs)
Metropolitan Manila Development Authority (MMDA)
responsible for planning, construction, and maintenance of national roads, highways, and bridges
DPWH
makes sure the country’s road network is reliable for transportation and economic growth
DPWH
oversees the transportation system (land, air, sea); works with DPWH for land transport policies
DOTr
responsible for registering vehicles, issuing driver’s licenses, and enforcing transportation laws
LTO
regulates toll roads and expressways
TRB
