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66
For work activities that require temporary lane closures, the Work Zone Crash Data Elements,
total safety impacts to the motoring public are less if the work is Collection and Storage Techniques,
done at night. Active work zones result in additional crash and Analysis Methods
costs regardless of whether the work is performed during the
day or at night. However, the amount of the increase is less if A need exists for both a state crash report form that includes
the work is done at night. This benefit of working at night, the recommended MMUCC data elements and highway-agency-
compared to doing the work during the day, extends across collected data elements for work zone crash analysis. Both
all AADTs, but it becomes much larger at higher AADTs. approaches to obtaining work zone crash information have
The severity of worker construction accidents is the same their advantages and disadvantages. The large amount of data
when working at night or during the day. The available data re- that police officers investigating a crash must collect on the
garding worker accidents did not allow a determination to be state crash reporting form limits how much specific detail
made as to whether such accidents are more frequent at night. about work zones can be included. In addition, certain types
However, the data do show that the accidents that do occur of technical data (type of devices in use, work zone design fea-
are no more severe at night than they are when they occur tures in place, etc.) cannot be effectively judged by police per-
during the day. sonnel who do not have this level of engineering expertise.
Collection of this type of data by highway agency personnel
is more appropriate. In addition, details about industrial
Management Policies, Procedures, accidents in the work area, something that is not typically in-
and Practices to Improve Nighttime vestigated via police crash reporting, can be better collected
and Daytime Work Zone Safety directly by the highway agency. The main drawback to high-
Several strategies have the potential to substantially lower the way agency collection of crash data is that it may miss those
increased crash costs resulting from work zones. Strategies that crashes and accidents that occur when project staff are not
appear to offer the greatest potential for crash cost reduction onsite when the event occurs (weekends, rain days, periods of
include the following: work inactivity, etc.).
The crash report form data elements currently recommended
· Practices to reduce the number and duration of work zones in the MMUCC guideline provide a good starting point for
required; establishing quality data on work zone crashes. Many of the rec-
· Use of full directional roadway closures via median ommended data elements provide information that can be
crossovers or detours onto adjacent frontage roads; useful in assessing how work zones are affecting safety at both
· Use of time-related contract provisions to reduce con- a project and process (regional or agency-wide) level. Some
struction duration; minor adjustments in several of the MMUCC data elements
· Moving appropriate work activities (i.e., those that require (changes to specific code descriptions and introduction of an
temporary lane closures) to nighttime hours; additional work-zone-specific code) could further enhance
· Use of demand management programs to reduce volumes the quality and quantity of crash data available to assess work
through work zones; and zone impacts on traffic safety.
· Use of enhanced traffic law enforcement. Exposure data at work zones are particularly needed to im-
prove process-level work zone crash analysis. Hours of activity
Other strategies may offer moderate reductions in crash costs (with and without lane closures or other capacity restrictions),
due to work zones, depending on conditions. Strategies that traffic volumes, etc. are needed to allow consolidation across
have been grouped into this category include the following: multiple work zones, to facilitate the computation of current
benchmarks, to track safety performance against those bench-
· Designing adequate future work zone capacity into marks over time, and to allow possible comparison across
highways; regions and states.
· Use of full roadway closures that require traffic detours Work zone crash analysis procedures should include both
onto adjacent surface streets; monitoring and post-hoc analysis components. Monitoring
· Use of ITS strategies to reduce congestion and improve procedures require quick access to crash data (the Ohio DOT
safety; manually collects hard-copy crash reports from law enforce-
· Improvement of work zone traffic control device visibility; ment offices on a regular basis during a significant project)
· Efforts to reduce flaggers' exposure to traffic; and and a simple method of determining whether certain roadway
· Efforts to reduce workspace intrusions and their segments or time periods in the project timeline are resulting
consequences--primarily at long-term, high-volume work in exceptionally more crashes than would be expected. These
zones. assessments serve as flags that the agency may need to evaluate
