Plaza Location and Collection Design Issues
As toll collection moves increasingly from cash-based to account-based, the need for traffic to stop to transact a toll decreases. In 1988, no tolls were collected electronically using radio frequency identification (RFID) technology. By the end of 2004, many US operators collected at least half of their tolls via electronic toll collection using RFID technology. Toll operators at the Florida’s Turnpike and Illinois Tollway have publicly stated they target 75% market penetration of their electronic toll collection programs.
Several new toll facilities have been built without cash toll collection, and several more are in development at the time of this writing. Necessity such as lack of right of way and partially completed “freeway grade” structures supported an all-electronic design for SR-91 in California and 407 ETR in Toronto, respectively. Florida’s Turnpike is preparing to completely remove the existing plazas from the 23-mile Sawgrass Expressway, and convert this facility to all-electronic toll collection.
The precedent set by the operation of non-stop toll facilities around the country is expected to result in toll customers increasingly not wanting to stop in a toll plaza environment, thereby limiting the life of conventional plazas, certainly less than the expected life of the tolled highways, bridges or tunnels.
Proposed plaza construction and modifications should be designed with anticipation of increasing ETC utilization, and eventual removal of conventional plazas, at least for the purpose of toll collection (bridge and tunnel operators may wish to retain plazas for inspection and security reasons). Plaza locations should be selected, whenever possible, to accommodate high-speed operations. Inherent in this approach, particularly for conversions, is the likelihood ETC will need to be supplemented by video tolling, temporary electronic passes, or some other means of high speed, non-stop collection to accommodate users without a transponder.
Plaza Location and Collection Guideline Development
Some design measures that would aide the owner in preparing for future growth in ETC usage are the following:
Provision for adequate ETC lanes to the extent that almost 100% of the approach roadway volume has an express lane or ETC dedicated lane to use. This suggests a 1:1 design relationship between ETC lanes and the approach or departure roadway lanes.
Simplification of the offered plaza lanes to only two types of toll collection. This greatly enables quick decision-making, which is increasingly the environment in which toll operations are conducted.
Economical conventional plaza design and construction is desirable where there is no existing regional use of ETC, cash collection metering affectively improves facility operations, and relatively low commuter traffic volumes are forecasted.
The expectation based on recent toll facility projects is new mainline toll plaza requirements will include non-stop ETC express lanes, and new ramp plaza requirements will include non-stop ETC dedicated lanes. In these cases, the driver approaching a plaza will have to make a choice between the non-stop lanes and the conventional plaza lanes or adjacent cash lane(s).
Plaza Location Guidelines
|Guideline||Plaza Locations Guideline 1|
|Title||Plaza and Interchange Intervals|
|Text||The 2001 AASHTO A Policy on Geometric Design of Highways and Streets (the “Green Book”) recommends separation of 1 mile (urban sections) or 3 miles (rural sections) between interchanges. This criteria should be used as a guideline for selection of new mainline toll plaza sites (i.e., the interstate standards require 1 mile to the nearest interchange in urban areas and 3 miles in rural areas).|
|Commentary||Although it may not be possible to meet this design guideline at bridge and tunnel crossings, the interval spacing minimums should remain a goal.|
|Guideline||Plaza Locations Guideline 2|
|Title||Site Selection and Sight Distance|
|Text||New toll plazas should be sited such that motorists will be able to see the plaza, while driving at posted speeds with adequate stopping sight distance before the queue zone. The plaza site should be on a tangent pavement section.|
|Guideline||Plaza Locations Guideline 3|
|Title||Ramp Plaza Movements|
|Text||New toll plazas should not have merging or diverging movements within the plaza approach and departure zones. New plaza construction should not occur within trumpet interchange areas, if possible.|
|Commentary||Some existing toll plaza locations have merging and diverging movements within the plaza approach and departure zones. Other appropriate treatment options could be applied to improve their operations.|
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