Toll Facility Safety Study Report to Congress - About

Toll Facility Safety Study Report to Congress
Appendix B – Literature Review
Background
There are many papers and reports that take an in-depth look at toll facilities and their
operational characteristics, but few studies exist that focus on safety at toll facilities. Those
studies that do exist and presented here according to the following four areas:
Safety Conscious Planning in Toll Facility Design.
Driver and Occupant Safety in the area of Toll Facilities.
Traffic Volume at Toll Plazas and the Impact on Safety.
Toll Collector Health and Safety.
Safety Conscious Planning in Toll Facility Design
Adequate toll facility design can have an impact on the safety of toll facilities once constructed
and operational. Several papers and reports reviewed by the project team describe case studies
and state-of-the-practice for toll facility design. In recent years, many of the studies deal with
effective design for facilities with a combination of conventional and ETC lanes.
In National Cooperative Highway Research Program (NCHRP) Synthesis 240 Toll Plaza Design
(Schaufler 1997), various practices are described related to the design, current practice, and use
of ETC. One of the major considerations of safety design is the use of safety devices on the
approach to toll islands. Devices include: concrete-filled steel bollards or I-beams, concrete
ramparts, barrier shapes, concrete crash blocks, impact attenuators, and frangible devices (such
as sand barrels). Toll agencies recognize that the purpose of the device is to protect the toll
attendants and redirect vehicles back into the toll lane and away from the toll plaza structure.
The synthesis report also describes the importance of appropriately designed traffic control
devices since a lack of consistency can be confusing to new patrons and older drivers. Inadequate
traffic control devices can also lead to slower processing of the tolls as well as abrupt maneuvers
in a plaza. The author states that toll plazas should have consistent signing, marking, and signal
practices to encourage consistent behavior.
A paper by McDonald and Stammer (2001) provides a contribution toward guidelines for toll
facility design. The authors state that safe toll facility design is more critical than ever when
ETC lanes are implemented. Safety considerations mentioned include the safety of drivers who
stop to pay a toll using conventional lanes, drivers who proceed without stopping when using
ETC lanes, and toll plaza workers. Various qualities of toll facilities change depending on the
agency as well as the individual facility including lane configurations, reversible lanes, taper
rates, transition lengths, lane width, and vertical geometrics.
With respect to lane configurations, toll facilities can contain a combination of toll payment
options including full service booths, automatic coin machines, and ETC. These ETC lanes can
be either express or dedicated depending on the facility. Care should be taken in the selection of
speed limits for ETC lanes where speeds can range from 5 to 45 mph for dedicated ETC lanes
and up to 60 mph or more for express ETC lanes. The use of reversible lanes is fairly common
especially in areas where there is a directional effect such as morning versus evening rush hour.
Appendix B – Literature Review Page B-1