Traffic Enforcement Strategies for Work Zones (2013)

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22 Introduction As previously stated, the utilization of law enforcement in work zones can have a significant safety benefit to both motorists and highway workers. However, the extent to which enforcement can be effectively utilized is dependent upon the design and traffic control characteristics of the work zone itself. Several work zone geometric design features can significantly detract from the ability of enforcement personnel to function either in an active enforcement or in a traffic-calming role within the work zone (or both). Similarly, choices regarding regulatory and advisory work zone speed limits, supplemental traffic control devices to manage speeds and raise driver aware- ness, and motorist notification of enforcement efforts can either benefit or constrain enforcement effectiveness. The following key points should normally be considered as part of the work zone planning and design process: • Establish realistic design speeds and speed limits; • Consider the need, extent, and type of police enforcement to be used; • Limit the length of shoulder closures; • Consider the need for enforcement pullout areas; • Consider speed management alternatives and supplements to enforcement; • Consider public awareness efforts regarding work zone enforcement; and • Consider motorist notification efforts regarding work zone enforcement. Establishing Realistic Design Speeds and Speed Limits Highway agencies have varying policies, guidelines, and standards for establishing work zone speed limits. In some states, traffic laws require speed limit reductions in work zones when workers are present, or during other specific conditions. Sometimes, the design speed through the work zone is used to determine the speed limit to be posted. It may be tempting to use a lower design speed within a work zone to minimize costs of temporary pavements for crossovers, restriping requirements, and other work zone features. However, in many instances, drivers do not voluntarily reduce speeds to that lower design speed, and simply posting a reduced speed limit in the work zone does not necessarily reduce speeds to the lower design speed. Consequently, this practice may produce a number of undesirable effects, such as: • Requiring a high and continuous level of enforcement during the project to maintain good driver compliance with the reduced speed limit; • Having a large number of drivers who are exceeding the design speed and posted speed limit; • Increasing speed differentials in the work zone; and • Decreasing the credibility of all types of traffic control devices in the work zone. Section 6B.01 of the MUTCD specifically states that road user movement should be inhibited as little as practical and that temporary traffic control at work sites should be designed on the assumption that drivers will only reduce their speeds if they clearly perceive a need to do so (13). Additional guidance pertaining to work zone speed reductions and speed limits is then found in Section 6C.01 pertaining to temporary traffic control (TTC) plan development, several excerpts of which are provided herein (13): “Reduced speed limits should be used only in the specific portion of the TTC zone where conditions or restrictive features are present. However, frequent changes in the speed limit should be avoided. A TTC plan should be designed so that vehicles can travel through the TTC zone with a speed limit reduction of no more than 10 mph.” “A reduction of more than 10 mph in the speed limit should be used only when required by restrictive features in the TTC zone. C h a p t e r 3 Enforcement Considerations in Work Zone Planning and Design

23 Where restrictive features justify a speed reduction of more than 10 mph, additional driver notification should be provided. The speed limit should be stepped down in advance of the location requiring the lowest speed, and additional TTC warning devices should be used.” “Reduced speed zoning (lowering the regulatory speed limit) should be avoided as much as practical because drivers will reduce their speeds only if they clearly perceive a need to do so.” “Research has demonstrated that large reductions in the speed limit, such as a 30 mph reduction, increase speed variance and the potential for crashes. Smaller reductions in the speed limit of up to 10 mph cause smaller changes in speed variance and lessen the potential for increased crashes. A reduction in the regulatory speed limit of only up to 10 mph from the normal speed limit has been shown to be more effective.” Reduced speeds should only be posted in the vicinity of work being performed or where necessitated by road con- ditions. Depending on state law, it may also be appropriate to post a reduced speed limit only during times of actual work activity (if the work activity itself is what constitutes the need for reduced speeds), and then cover or remove the signs when work is not active. Various technologies also exist to assist in implementing these types of short-term speed limits, a couple of which are shown in Figure 13. Considering the Need, Extent, and Type of Police Enforcement to Be Used in the Work Zone Certain work zone design features and work activities may trigger the need for incorporating work zone enforcement into the overall transportation management plan for a particular project. Early recognition of the potential need for enforcement at an upcoming work zone is beneficial from a programmatic perspective, as it allows agencies to better estimate costs and manpower resources that will be needed, as well as to identify time periods and regions where possible resource constraints that could develop so that contingencies can be established. Certain states have legal requirements regarding the use of enforcement in some categories and certain work zones. Meanwhile, some highway agencies have pre-established criteria regarding enforcement use and even the type of enforcement strategy incorporated into their policies and procedures. In some instances, the amount of funding available for enforcement use in work zones serves as the controlling criteria. In these instances, it is very important that projects that are likely to benefit most significantly from enforcement use be identified early so that they can be considered in the overall resource allocation process. While identification of enforcement needs during project planning and design is highly desirable, it is not always possible. Changes in the type of work being performed, field changes in the overall traffic control plan and project phasing, or higher than expected crash rates, are all possible reasons for making a decision to incorporate enforcement into a project after it begins. Most highway agencies recognize that this uncertainty exists, and account for possible additional needs in their work zone enforcement funding and resource allocation efforts each year. Work Zone Design Features Related to Enforcement Limiting the Length of Shoulder Closures As shown in Figure 14, shoulders must be closed in many work zones, using portable concrete barrier or other devices, for work activities or for use as temporary travel lanes while work occurs on another part of the roadway cross-section. Unfortunately, such closures eliminate locations for enforce- ment personnel to safely position themselves and/or pull over violators to issue a citation. If used, shoulder closures should be kept as short as possible to minimize their adverse effects on enforcement activities. Generally speaking, such shoulder closures should be limited to three continuous miles or less (14). Limiting shoulder closure lengths also improves overall traffic safety and flow, ensuring that there will be opportunities for disabled vehicles to find refuge on a shoulder section instead of stopping in an active travel lane. Considering the Need for Enforcement Pullout Areas In some cases, it may not be possible to limit shoulder clo- sures to three miles. In these instances, consideration should be given to including periodic enforcement pullout areas within Figure 13. Examples of some technologies to implement short-term speed limits in work zones.

24 the work zone. Enforcement pullout areas must be adequately designed to allow them to be properly used by enforcement personnel and motorists. Enforcement pullout areas in work zones should be: • Wide enough to allow enforcement personnel to exit their vehicle and safely move in the area to issue a citation; • Long enough to allow safe entry to and exit from the normal traffic stream; and • Spaced close enough to be useful to enforcement personnel, but far enough apart so that they do not interfere with work progress. Experiences with enforcement pullout areas in high- occupancy vehicle lanes indicate that the width of the pullout should be at least 12 feet (15). Where possible, pullout areas should be located on the right side of the roadway to avoid creating driver expectancy problems, and should preferably be 0.25 miles long to allow adequate space for an enforcement vehicle and the stopped vehicle to safely pull into the area, and have enough space left to safely pull out of the area once the enforcement activity has been concluded (see Figure 15). Research indicates that pullout areas spaced approximately every 3 miles are an effective compromise between enforce- ment needs and those of the highway contractor completing Note: refer to the MUTCD (13) and the AASHTO Roadside Design Guide (16) for proper treatment of the ends and slope of the concrete barrier Figure 15. Example work zone enforcement pullout area (4). Figure 14. Lengthy shoulder closures make enforcement efforts in work zones more difficult.

25 the work (14). The location of the pullout area should be such that there exists adequate sight distance upstream and downstream. Speed Management Alternatives and Supplements to Enforcement For work zones where traffic demands do not justify the use of enforcement or where enforcement needs exceed enforce- ment resources, other speed management technologies and supplements can be considered for implementation in the work zone. Common speed management technologies include: • Speed display trailers; • Radar-activated portable changeable message signs (PCMS); • Citizen-band radio information systems; • Temporary transverse rumble strips; • Drone radar emitters; and • Narrowed lanes using channelizing devices. Speed display trailers and radar-activated PCMS are similar in that both include a radar device pointed upstream to measure the speed of the approaching vehicle, and display that speed electronically (see Figure 16). The speed display trailer is more limited in that it will only display the vehicle speed, whereas a radar-activated PCMS with radar can display other messages (e.g., YOU/ARE/SPEEDING, SLOW/DOWN/NOW) in addition to actual speeds. Early experiences with these types of devices found that some drivers tested their vehicles by see- ing how fast they could get the display to read. Consequently, both of these types of displays now incorporate a maximum display threshold into their logic. These devices can result in small (2–3 mph) reductions in average speeds, although reductions as much as 10 mph have been documented in a few instances. The effectiveness of these devices is depen- dent upon roadway geometrics (more effective on two-lane highways than on multi-lane facilities) and traffic volumes (the devices often do not provide accurate speed indications when traffic volumes are too high). The devices also tend to be ignored by more drivers if the work zone speed limit is far below the normal operating speed of the facility and there is no obvious reason for the reduced speed limit. Citizen-band (CB) radio information systems are self- contained units that allow an agency to record a message that is then continuously broadcast over a selected CB channel. These devices target primarily long-haul truckers who rely on CB radios for communication, and can achieve small (2 mph or less) reductions in truck speeds, depending on the message used. This technology is most applicable for address- ing truck-specific hazard warnings within work zones. One concern with this technology is that it may increase speed differentials between automobiles and trucks. For work zones that are stationary for several hours or days, temporary transverse rumble strips can be placed in advance of the work zone or at key locations within the work zone where additional driver attention is desired. These devices do not result in large decreases in speed (generally no more than 2 to 5 mph), but provide both tactile and auditory feedback to the driver that is believed to increase alertness. Some types of temporary rumble strips are adhered to or cut into the pavement. Other temporary rumble strips are heavier, and are simply placed on the pavement without the need for adhesives or other connection to the pavement. Drone radar transmitters have been on the market for several years now. These devices consist of a small k-band radar transmitter and battery housed in a case. These transmitters can be attached to work vehicles or traffic control devices within or upstream of a work zone to activate radar detectors in approaching vehicles. The effects of the transmitters on average speeds are fairly modest (3 mph or less), since only a limited number of vehicles have radar detectors in them. The devices may also increase speed differentials between vehicles with radar detectors and those without, and so should not be used in locations where a reduced speed limit that is far below the normal operating speed of traffic is posted. However, (a) Speed Display Trailer (b) Radar-Activated Portable Changeable Message Sign Figure 16. Speed display trailer and radar-activated portable changeable message sign.

26 it is commonly assumed that those drivers who have radar detectors generally travel faster than those without detectors, implying that this technology may be beneficial in reducing the percentage of very high speed vehicles in the traffic stream. One final consideration is that a number of states prohibit radar detectors in commercial vehicles, and a few states pro- hibit detectors in all types of vehicles. Narrowed lanes using channelizing devices is another tech- nique that has been shown to reduce speeds slightly within work zones. The placement of channelizing devices so as to create 11 or even 10.5 foot travel lanes can result in speed reductions up to 5 mph, although the reductions will nor- mally be smaller than that. Also, the effect of this technique will be greatest when only a single lane is available for travel through the work zone, since the channelizing devices do not provide the same “closed in” sensation to drivers when there are two or more lanes traveling in the same direction. One disadvantage to this technique is that it will increase the frequency of channelizing devices that are knocked down or out of position within the work zone, which will require additional effort by traffic control personnel to constantly maintain the devices in the correct arrangement. Another possible concern is that the combination of narrowed lanes and channelizing devices may reduce lane capacity, resulting in increased congestion and development of traffic queues. Table 4 summarizes the advantages, disadvantages, and key deployment considerations for each of the technologies discussed herein. Public Awareness for Work Zone Safety and Enforcement Public awareness programs for work zone safety have been in place for many years. Nationally, the “Give ’em a Brake” program is perhaps the most common, although several states have developed their own programs and slogans, such as the “Slow for the Cone Zone” program in California (see Fig- ure 17). Other unique initiatives can be found on the National Work Zone Safety Information Clearinghouse website (www. workzonesafety.org) by clicking on the “public awareness” link. Agencies should periodically review the programs in place elsewhere, and consider adapting one for use in their jurisdic- Technology Advantages Disadvantages Deployment Considerations Speed display trailers - Well understood by motorists - Easily deployed and moved - Relatively low cost - Ignored if reason for speed reduction is not apparent - Overused in some areas, reducing credibility - Does not work well on high-volume roadways - Should be moved regularly - Best use is upstream of a specific hazard - Important to ensure adequate sight distance to the device - Should be positioned to minimize risk of impact by errant vehicle Radar-activated PCMS - Can display speeds or other speed-related messages - Display is higher off the ground, increasing sight distance - Can be used for other than speed-related messages if desired - More costly than speed-display trailers - Requires sign programming expertise (setting messages, thresholds, etc.) - The display of speeds will not work well on high-volume roadways - Best use is upstream of a specific hazard - Should be positioned to minimize risk of impact by errant vehicles CB radio information systems - Does not contribute to visual information workload - Allows for truck-driver-targeted messages to be disseminated - Allows longer messages - Allows drivers to hear message more than once - Proprietary device - Information dissemination is limited to those with CB radio receivers - Most effective where most truck traffic is long-distance haulers - Message design should be based on highway advisory radio (HAR) guidelines Transverse rumble strips - Provides both tactile and auditory warning to raise driver alertness level - Fairly low cost - Effect on vehicle speeds is minimal - Strips adhered to the pavement cannot be easily reused at another location - Noise generated by rumble strips may be objectionable near residential areas Drone radar emitters - Low cost - Easily moved and removed - Warning effect only reaches those with radar detectors - Can increase speed differentials between vehicles with and without detectors - Radar detectors are prohibited in some states - Devices are often vandalized or stolen, so use is most effective during work activities and removed immediately afterwards Narrowed lanes with channelizing devices - Can be created during traffic control device setup - Requires constant monitoring to maintain devices in proper locations - may reduce capacity and increase congestion and queues - Effect is likely to be greater with larger devices (i.e., drums) and closer device spacing PCMS = Portable Changeable Message Sign Table 4. Speed management alternatives and supplements to enforcement.

27 tion. Changing the way in which the message to slow down and pay attention in work zones is presented should help keep the message fresh in the minds of motorists, and help encourage good driving behavior in work zones. A new work zone public awareness program is best “rolled out” at the beginning of the construction season, in conjunction with the National Work Zone Awareness Week that occurs the first week of April each year. Motorist Notification for Work Zone Safety and Enforcement In most states, fines for speeding and/or other traffic vio- lations are doubled or otherwise increased in work zones. In many cases, the fines are increased if workers are present at the time of the violation. The law in some states requires signing to notify the driver about the increased fines. Implementation of the increased fine laws can be problem- atic for enforcement personnel in work zones that are extremely lengthy or when work activities occur outside of what are con- sidered normal working hours. In these situations, officers have difficulty knowing for certain whether workers are indeed pres- ent. Likewise, motorists approaching the work zone do not yet know whether workers are present and that fines are increased. One way to address this issue is through the implementation and use of special signing to notify motorists and enforcement personnel that a work zone exists and that workers are pres- ent at the work site. A highway agency inspector or contractor supervisor is responsible for activating this workers present sign at the beginning of a work shift, and then turning it off when the shift is over. This last task is particularly important, as failure to de-activate the sign will quickly degrade its credibility with both the motoring public and law enforcement personnel. Perma- nent and portable changeable message signs could also be used to remind motorists that fines are increased for traffic violations in work zones, as illustrated in Figure 18. Normally, motorists need not be notified about active enforcement activities currently occurring in a work zone. One goal of work zone enforcement efforts is to establish an expectation that enforcement personnel may be present in any work zone at any time, and thus discourage drivers from ever violating traffic laws. That being said, there are two specific active enforcement strategies where the use of real- time notification of enforcement efforts does make sense. The first of these is in conjunction with “Operation Hardhat” pack-enforcement initiatives. Although the placement of an officer in a construction worker vest and hardhat within the work zone is intended to allow covert enforcement efforts to occur, this approach can be viewed negatively by the public as a type of speed trap intended solely for increasing revenues, especially if the speed limit has also been reduced through the work zone. If efforts are made to warn approaching motorists that an enforcement effort is occurring in the work zone, the perception of a speed trap can largely be avoided. An example of an acceptable message on a typical 8-character, two-phase PCMS to notify approaching drivers is shown in Figure 19. In certain cases, the highway and enforcement agency may even choose to notify the media about the work zone location where the enforcement efforts will occur that day. Another enforcement strategy that usually requires motorist notification in advance of the enforcement location in the work zone is semi-automated or automated speed enforcement tech- nology. This warning is likely to be explicitly required as part of the enabling legislation in order to make the citation valid (the Figure 17. Examples of speed-related work zone public awareness campaigns (17).

28 signing required for the automated enforcement program in Illinois is illustrated in Figure 20). Again, the primary concern is with avoiding the perception that the enforcement effort is intended for revenue generation rather than safety enhance- ment. Consequently, agencies will generally err on the side of caution and provide multiple opportunities for motorists to slow down prior to reaching the enforcement point. In addi- tion to static advance signing left in place at all times, speed display trailers or boards that may be mounted on an enforce- ment van provide a real-time notification to speeding driv- ers to allow them to reduce their speed prior to reaching the enforcement point. Figure 18. Examples of motorist notification signing pertaining to work zone enforcement. Figure 20. Example of motorist notification signing used with the Illinois work zone automated speed enforcement program. Figure 19. Example of advance warning of work zone enforcement activities. SPEEDS ENFORCED AHEAD SLOW DOWN NOW