Evaluating Alternative Operations Strategies to Improve Travel Time ...

SHRP 2 L11: Final Report
5.7.Lane
Treatments
Managed
Lanes: High-
Occupancy
Vehicles (HOV
) lanes, Highoccupancy
Toll
(HOT) lanes,
Truck-only Toll
(TOT) lanes
Overall Cost Range* :Low - 200K but < 1 million
High - >1 million
Physical
Bottlenecks,
Fluctuation in
Normal Traffic,
Traffic
Incidents
Provides
reduction in
travel times up to
16%.
Medium
-High
2-D
Temporary signs are often used in work zones to update travelers of ongoing or expected changes
in normal travel conditions.
Geometric Design Treatments
These treatments primarily apply to facilities with existing weaving sections and horizontal or
vertical alignment deficiencies. In the case of weaving sections, these treatments apply primarily to
freeways. The improvement to or removal of weaving sections can be applied in any area (urban,
suburban, and rural) where recurring congestion occurs. It can also be applied on a facility in need
of higher safety performance - where crashes have been known to create non-recurring congestion
conditions. The improvement of horizontal and/or vertical alignments is most-often applied in the
case of older facilities of all types and settings.
Signal Retiming/ Optimization
This treatment can be applied at multiple intersections along arterials, on local roads, or at
individual intersections. Because traffic signals can be found in urban, suburban, and rural settings,
this treatment can be applied in all of the setting types. Typically, this treatment is applied to
address recurring congestion issues, but it has the flexibility to also be applied in non-recurring
congestion situations to temporarily improve the flow of traffic (for example, through the
implementation of a special-events timing plan).
Advanced Transportation Automation Systems, Signal Priority, and Automated Vehicle
Location (AVL)
These three treatments have a variety of applications associated with them. In the case of an
Advanced Transportation Automation System, the application would be limited to those facilities
instrumented to automate all or part of the driving task for private automobiles, public
transportation vehicles, commercial vehicles, and maintenance vehicles through cooperation with
an intelligent infrastructure. Given the costs of instrumentation, this treatment is likely to include
localized operations before regional operations are achieved. In the cases of Signal Priority and
AVL, these treatments can be applied locally or regionally depending on the institutional
frameworks in which they are deployed. Signal priority applications are typically limited to transit
vehicle operations while AVL is commonly applied to a wider range of vehicle types including
transit, fire, and emergency response vehicles.
Ramp Metering, Ramp Closure
The application of Ramp Metering is limited to freeway facilities and is most-commonly applied in
larger urban areas. This treatment can be applied in locations where there is a need to control the
manner and rate in which vehicles are allowed to enter a freeway. It also can overcome issues with
safety and geometric design at merging sections on a freeway. Ramp closures are limited to
freeway facilities in most cases and are applicable in all areas (urban, suburban, and rural) where
an operational benefit could be achieved through the closing of a ramp.
OPERATIONS STRATEGIES AND TREATMENTS TO IMPROVE TRAVEL-TIME RELIABILITY Page 83