In Texas, short term work zone speed limits (less than 12 consecutive hours) are to be used when workers or equipment are not behind concrete barrier, work activity is within 15 feet of the pavement edge, or work is actually occurring on the pavement. In these situations, short term work zone speed limit signs should be posted and visible to the motorists only when work activity is present and covered or removed when no work activity is present. The daily install/removal or uncover/cover process of signs represents an additional task for the contractor that reduces overall work productivity. Thus, some contractors choose not to cover or remove signs; others simply forget, resulting in the short term regulatory work zone speed limit extending into time periods when there is no apparent need for a speed limit reduction. Recently, new sign technologies have been developed that may simplify the short term work zone speed limit implementation process, and could enhance use of short term work zone speed limits in general. However, such technologies have not been used extensively for work zone speed limits in Texas. Thus, researchers at the Texas Transportation Institute used field studies and motorist surveys to verify that electronic speed limit (ESL) signs and flexible roll-up work zone speed limit signs areeasily implemented, effective at reducing speeds, and understood by motorists. Based on these results, researchers recommended the use of ESL signsand flexible roll-up work zone speed limit signs.
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