Requirements for Crash Testing of Work Zone Devices
On July 27, 1997, the FHWA's Office of Engineering issued a guidance memo mandating that all work zone devices, used on the National Highway System (NHS), be crash tested to NCHRP 350 requirements. This memo went on to divide many of these devices into four (4) categories, with each having their own level of testing requirements and compliance dates.
- NCHRP Report 350: Devices in Work Zones - Category 1
- Items that are small and lightweight, channelizing and delineating devices that have been in common use for many years and are known to be crash worthy by crash testing of similar devices or years of demonstrable safe performance. These include cones, tubular markers, flexible delineator posts, and plastic drums with no attachments. These devices may be allowed for use on the NHS based on the developer's self-certification.
- NCHRP Report 350: Devices in Work Zones - Category 2
- Devices that are not expected to produce significant vehicular velocity change, but may otherwise be hazardous. Examples of this class are barricades, portable sign supports, intrusion alarms, and drums, vertical panels, or cones with lights. Testing of devices in this category will be required. However, they may qualify for the reduced testing requirements. The compliance date for this category is October 1, 1998.
- NCHRP Report 350: Devices in Work Zones - Category 3
- Hardware that is expected to cause significant velocity changes or other potentially harmful reactions to impacting vehicles. Hardware in this category must be tested to the full requirement of NCHRP 350. Barriers, fixed sign supports, crash cushions, and other work zone devices not meeting the definitions of Category 1 or 2 are examples from this category.
- NCHRP Report 350: Devices in Work Zones - Category 4
- Portable or trailer-mounted devices such as Arrow Displays, Temporary Traffic Signals, Area Lighting Supports, and Portable Changeable Message Signs. After compliance date of October 1, 2002, this class of devices may not be used unless they are placed behind crash worthy barriers or shielded with TMAs or crash cushions.