American Society of Civil Engineers (ASCE) is devoted to the protection of the public's health, safety and welfare. Transportation safety is a critical part of it. The Transportation Safety Committee of ASCE’s Transportation & Development Institute (T&DI) is charged to disseminate safety information and to provide education and training pertaining to safety issues related to the planning, design, construction and operation of transportation facilities, with emphasis on increasing safety awareness for all aspects of transportation infrastructure operations and improvement. As such, transportation safety is covered as part of the content delivered by ASCE through its continuing education courses, journals, and conferences. ASCE also helps disseminate transportation safety resources and content from other sources. An example of this is the Unsignalized Intersection Improvement Guide.


On Saturday, July 2, 2016, about 5:16 a.m., a 2005 Freightliner truck-tractor in combination with a semitrailer struck a 1979 Blue Bird passenger bus at the intersection of US Highway 98 (US-98) and State Road 363 near St. Marks, Florida1. The bus, traveling south on State Road 363, failed to stop at the intersection, where traffic was controlled by a stop sign and overhead flashing red traffic control beacons, and proceeded directly into the path of the truck-tractor. The truck-tractor, traveling west on US Highway 98, had limited sight distance as it approached the intersection, which was controlled, in this direction, by overhead flashing yellow traffic control beacons. The truck struck the left side of the bus, then rapidly rotated counterclockwise; its right-side-mounted diesel fuel tank breached, igniting a fire. The front of the semitrailer then struck the left side of the bus.

The truck was occupied by the driver and a passenger, and the bus was occupied by the driver and 33 passengers, most of whom were migrant agricultural (AG) workers. Tragically, the truck driver and three bus passengers were killed. The bus driver, 28 bus passengers, and a passenger in the sleeper berth of the truck were injured. The National Transportation Safety Board (NTSB) determined that the bus driver’s unfamiliarity with the rural roadway, which was dark and poorly lit, contributed to the crash. In addition, as part of a pavement improvement project, the Florida Department of Transportation (FDOT) had removed the permanent transverse rumble strips that might have alerted the bus driver to the stop-controlled intersection ahead. FDOT had neither reinstalled the strips before the crash, nor used temporary transverse rumble strips as an interim measure.

Measures to Improve Safety

One way to mitigate such accidents is by implementing effective roadway engineering countermeasures at unsignalized intersections, and members of the National Association of Towns and Townships are uniquely positioned to make a difference on our nation’s roadways. Members can turn to several available resources for guidance when evaluating unsignalized intersections and identifying opportunities to enhance their safety, such as the Unsignalized Intersection Improvement Guide (UIG), a web-based program with an interactive interface. Possible measures to improve safety at these intersections include2:

  • Installing a stop beacon
  • Installing a warning beacon on a standard regulatory or warning sign
  • Using LED units within a regulatory or warning sign
  • Installing reflective panels on signposts
  • Adding retroreflective sheeting to the perimeter of a warning sign
  • Adding a duplicate regulatory or warning sign
  • Installing pavement word or symbol markings
  • Installing an intersection conflict warning system
  • Installing transverse rumble strips on the intersection approach
  • Installing intersection lighting
  • Implementing an all-way stop control
  • Installing a traffic control signal
  • Installing a roundabout

A safe system approach that incorporates roadway engineering countermeasures can save lives.

1Agricultural Labor Bus and Truck-Tractor Collision at US-98-SR-363 Intersection Near St. Marks, Florida, July 2, 2016, NSTB/HAR-17/05. Available at

2Unsignalized Intersection Improvement Guide. Available at