Work Zone Speed Management (2015)

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54 chapter six TRADITIONAL “HUMAN” WORK ZONE SPEED ENFORCEMENT INTRODUCTION This chapter discusses non-automated work zone enforcement techniques; that is, policing by humans. Automated and semi- automated enforcement technologies are discussed in chapter seven. State DOTs and their partner law enforcement agencies apply a wide range of policing philosophies and methods for work zone speed enforcement, which are summarized in Table 11. In some states, such as South Carolina, the view is that the police should be actively patrolling the work zone and issuing as many citations as possible (J. Sease, personal communication, 2014). In other states, such as Pennsylvania, Vermont, and Virginia, the goal is a very visible presence of police cars in the work zone with their lights flashing, and citations are seldom issued except to extreme violators (M. Briggs, personal communication, PennDOT, 2014; B. Nyquist, Vermont Agency of Transportation, personal com- munication, 2014; D. Rush, VDOT, personal communication, 2014). Although law enforcement agencies often suggest that the number of citations issued is a measure of the effective- ness of work zone speed enforcement, a Canadian work zone speed management report notes that, “decreasing numbers of citations may indicate improved safety conditions in the work zone, provided the posted speed limit is realistic for the conditions” (Harmelink and Edwards 2005). A report from the Global Road Safety Partnership empha- sizes the value of enforcement methods based on an any- where, anytime approach to deter all speeding on the roadway network (Howard et al. 2008). The goal is to send a clear message that speeding is illegal and unacceptable behavior, and at odds with the interests of the community. Although the report does not focus on work zones, the following text appears to be particularly relevant to work zone enforcement techniques: How speed enforcement is done determines whether its principal effect is through specific or general deterrence. • Operating highly visible (police or fixed-camera) speed enforcement in the same areas all the time is likely to result in drivers being deterred from speeding only in those specific areas. • Operating a mix of highly visible and strategically directed police patrols or speed cameras increases pub- lic perception that speed enforcement can happen any- where and at any time. The unpredictability of where and when speed enforcement operations take place will have a more general deterrent effect by encouraging drivers to drive within the speed limit no matter where or when they are travelling. Many work zones lack sufficient physical space for inter- cepting speeders and issuing citations; as a result, some juris- dictions such as Virginia use multiple-officer techniques, with one officer positioned in the work zone as an observer and one or more police vehicles downstream of the work zone to pull over speeders and issue citations (D. Rush, personal communication, 2014). To provide a wider field of view, a variation of this tactic is to position the observer on an over- pass, a practice widely used in Texas. South Carolina typi- cally uses four troopers in a work zone to issue citations and saturate a work zone with enforcement presence (J. Sease, South Carolina DOT, personal communications, 2014). Obtaining sufficient police resources for work zone enforce- ment remains an ongoing concern in many states, and is a limiting factor for many types of work zone enforcement. This issue has many dimensions: budget and finance, human resources and labor relations, and organizational and juris- dictional factors. To a large extent each state’s situation is a unique reflection of its state laws, collective bargaining agree- ments, and the established degree of cooperation or competi- tion between state, county, and local law enforcement agencies. As Pigman et al. (2006) noted: The state . . . does not have enough police to be at all work zones. The commissioner noted that [the state] needs to use local police officers for work zone enforcement even on state highways and interstates. (emphasis added). In recent years there have been increased efforts to train law enforcement personnel on work zone enforcement techniques. For example, the National Highway Institute (NHI) offers a two-hour, web-based training course Safe and Effective Use of Law Enforcement Personnel in Work Zones (NHI 2014). POLICE ENFORCEMENT Police enforcement has repeatedly been shown to be one of the most effective speed management techniques in work zones. Law enforcement presence has also been shown to

55 pullouts (also called pullovers or lay-bys) in the work zone; Ullman and Schrock (2011) developed design recommenda- tions for the length and spacing of such areas. Although federal regulations do not require law enforce- ment in all work zones, federal regulation 23 CFR 630 Sub- part K does require all state agencies to have a policy for the use of enforcement in work zones on federal-aid projects. Guide- lines on the Use of Law Enforcement in Work Zones developed by the Roadway Safety Consortium, summarizes the avail- able guidance on the use of law enforcement in work zones (Roadway Safety Consortium 2011). NCHRP Report 746: Traffic Enforcement Strategies for Work Zones published in 2013 provides guidance on safe and effective deployment of traffic enforcement techniques in work zones on highways with speed limits of 45 mph or greater (Ullman et al. 2013). To avoid duplication, readers are referred to NCHRP Report 746 reduce speed variation and undesirable driving behaviors such as tailgating and unsafe lane changing. Additional benefits include greater motorist alertness, quicker response to incidents and crashes in a work zone, and the ability to perform traffic control, if necessary. Some of the disadvantages and limitations of using police enforcement in work zones include reduced availability of officers for other law enforcement duties, offi- cer safety in the work zone environment, enforcement-related costs, and cooperation and coordination between law enforce- ment, the contractor, and the highway agency. Another poten- tial disadvantage is reduced work zone traffic throughput, for example Avrenli et al. (2012) reported that police presence can decrease free-flow speed by 6.3 mph and capacity by 50 pas- senger cars per hour per lane (50 pcu/ln). A typical constraint for active enforcement by police is the lack of space for maneu- vering and apprehending speeders in work zones. This can be mitigated to some degree by providing enforcement pads or Tactic Description Advantages Disadvantages Active Enforcement Officers actively identify, pursue, and cite violators in a manner similar to ordinary highway patrols. • Maintains the potential threat of citation • Loss of effect of enforcement once the officer pursues or is engaged with a violator Circulating Enforcement Officers circulate the work zone in vehicles • A circulating patrol at the speed limit can serve as a “pilot car” and reduce speed throughout the work zone. • Does not limit the effectiveness of enforcement to a specific location • Can simultaneously serve roadway monitoring and incident detection/response role • Loss of speed reduction at certain locations such as work activity area Stationary Enforcement Officer and vehicle parked in or upstream of work zones; not pursuing violators. Some have flashing lights on, while some do not. • Sustained effect on speeds of vehicles • Loss of potential threat of citation and consequent lack of driver response Police Traffic Controller Officer positioned outside vehicle for reducing speeds, not traffic control duties • Visibility of officer can increase speed reductions. • Increased risk for officer • Officer cannot easily pursue a violator Enforcement Pack One officer identifies violators and notifies another officer(s) downstream of the work zone to cite them. Some agencies use covert officers for identifying violators. • Safer as it eliminates the pursuit of violators through work zones • Speed reduction effect at the upstream location remains • Citation downstream ensures credibility of enforcement is not lost • Multiple officers are available in case of incidents in work zone. • Increased costs • Greater requirement of law enforcement resources • Violators are not pulled out of traffic stream till they exit the work zone Aerial Enforcement Aircraft or helicopter used to monitor speeds. Violators are identified and an officer on the ground is notified to stop and cite violators • Does not require officers in work zone and has benefit of covert enforcement. • Requires roadway to be marked for measuring speeds. Maintaining the markings through different stages of work activity can be difficult. Relatively expensive and rarely used. TABLE 11 OVERVIEW OF WORK ZONE ENFORCEMENT TECHNIQUES

56 MnDOT examined the effectiveness of stationary police enforcement at work zones on a rural interstate, an urban free- way, and a metro location (Maze et al. 2000). The 85th percen- tile speeds were reduced from 51 to 43 mph, 66 to 58 mph, and 58 to 47 mph, respectively, at the three locations. Research- ers from Illinois evaluated the effectiveness of stationary enforcement at two work zones in Illinois (Benekohal et al. 2010; Hajbabaie et al. 2011). Stationary enforcement reduced the mean speeds significantly by 5 to 7 mph, for the gen- eral traffic stream as well as free-flowing vehicles. Lodes and Benekohal (2013) compared the speeds of individual drivers near stationary enforcement and 1.5 miles down- stream. The paired data were used to quantify the speed change behavior and spatial effect of the treatments. The vast majority of drivers (92%) sped up after passing the treatment location, indicating that spatial effectiveness of stationary enforcement is limited. Oregon DOT used three stationary law enforcement vehicles in a pilot evaluation to reduce the speed limit from 65 mph to 35 mph in two stages of 15 mph each (Gambatese and Zhang 2013). Figure 34 shows the traffic control plan used for this purpose. The 85th percentile speeds for passenger cars and trucks were 36 mph with standard deviations of 4 mph and 3 mph, respectively. for guidance on planning, design, and operation of traffic enforcement techniques, as well as administrative issues (the scope of this synthesis report is limited to discussion of the effectiveness of various police enforcement techniques). A variety of enforcement techniques have been used in work zones. Technique selection is influenced by site condi- tions, the nature of the work operations, physical constraints such as the availability of enforcement pads or pullouts, staff- ing and budgetary constraints, and institutional and organiza- tional factors. Table 11 lists several common techniques and summarizes strengths and weaknesses that have been reported in the transportation literature. ENFORCEMENT EFFECTIVENESS RESEARCH FINDINGS A number of studies have examined the speed reduction effects associated with various enforcement techniques. It is important to recognize that these observations are influenced by the meth- ods used to collect the speed data, the location where the speeds were measured (e.g., immediately adjacent to the police vehicle or further downstream), the work zone site conditions, and the severity of the speeding in the absence of enforcement, which in some cases is related to the traffic volume through the site. FIGURE 34 Traffic control plan for 30 mph reduction in Oregon (Gambatese and Zhang 2013).

57 with 8.8 mph from the traditional approach (Carpenter et al. 2012). ACOZEEP also resulted in vehicles maintaining lower speeds for a longer distance. ACOZEEP was recommended in moderate-to-lengthy work zones where there is an uninhib- ited field of view. ACOZEEP is less recommended if the field of view is inhibited or when there are natural features that result in speed reduction in the work zone. Washington State’s Traffic Manual (Washington State DOT 2009) calls for two or more stationary patrol vehicles for work zones with a work area greater than 1,000 ft in length. Texas and South Carolina also use enforcement pack techniques in work zones. DOTs and law enforcement agencies in Florida, Illinois, New York, and Pennsylvania have reported the use of the stealth work zone speed enforcement tactic illustrated in Figure 35. In this technique, an upstream officer (sometimes dressed as a worker) is positioned inconspicuously in the work activity area to identify violators using a radar or Lidar unit. A down- stream officer(s) intercepts and tickets the violators. Several names have been used to describe and publicize this tactic, including Operation Hard Hat, Operation Yellow Jacket, and Operation Orange Squeeze. The latter term is used on the Penn- sylvania Turnpike, where patrol commander Captain Gregory Bacher describes the objective as follows: “Motorists won’t know where or when troopers will be in construction vehicles, so they need to always obey the posted speed limit and travel with headlights on in active work zones” (PTC 2014). Local media reported that 28 tickets were issued in 90 minutes in one such operation in Delaware County, Pennsylvania, in 2012 (Scharr 2012), but no formal data on the speed reduc- tion effectiveness of this tactic have been published. Simi- larly, no data on the effectiveness of aerial enforcement have been reported in the literature. Noel et al. evaluated stationary enforcement with active radar and police traffic controller techniques on a six-lane freeway in Delaware (Noel 1987; Noel et al. 1988). Data were collected under one-lane and two-lane closure conditions and short-term and long-term data collections. Mean speeds were reduced by 2.4 and 5.1 mph for one-lane closure under sta- tionary and police traffic controller approaches, respectively. For a two-lane closure, speeds decreased further by 6.3 mph for police traffic controller and counterintuitively increased by 3.6 mph for stationary enforcement. Circulating enforcement is reported to be less effective than stationary enforcement. Ullman et al. (2013) reported that sta- tionary enforcement results in a speed reduction of about 5 to 7 mph and circulating enforcement results in a reduction of 2 to 4 mph. Benekohal et al. (1992) reported that average speeds of cars and trucks were 4.3 to 4.4 and 4.3 to 5.0 mph lower with circulating enforcement. Richards et al. (1985a, b) evaluated the effectiveness of stationary and circulating enforcement at six work zones on rural and urban highways in Texas. Stationary enforcement resulted in reduction of mean speeds by 4 to 12 mph and circulating enforcement resulted in a reduction of 2 to 3 mph. California uses the Augmented Construction Zone Enhanced Enforcement Program (ACOZEEP), which is essentially an enforcement pack tactic with one enforcement vehicle visible near the beginning of the work zone and one or more down- stream for citing the violators. Caltrans compared ACOZEEP with their typical approach (stationary enforcement) of using only one enforcement vehicle parked near the beginning of a work zone. Results indicate that ACOZEEP resulted in a higher average speed reduction of 9.6 mph compared FIGURE 35 Operation Hardhat tactic described in NCHRP Report 746 (Ullman 2013).