Work Zone Speed Management (2015)

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58 chapter seven AUTOMATED WORK ZONE SPEED ENFORCEMENT INTRODUCTION Automated speed enforcement (ASE) is also known as photo speed enforcement, photo radar speed enforcement, speed photo enforcement, or simply speed cameras. In the United Kingdom, the acronym TASCAR (Temporary Automatic Speed Camera at Roadworks) is used specifically in the context of work zones. Automated enforcement has been in use since at least 1973, when it was deployed to address excessive speeds on a downgrade section of an autobahn near Elzer Mountain, Germany (Lamm and Kloeckner 1984). The technique involves the use of permanent or temporary equipment that determines vehicle speeds, photographs the vehicle license plate, and mails an infraction notice to the registered owner of the vehicle. Although automation assists with the enforcement process, automated enforcement is generally not robotic. Commercially available systems vary in the degree to which humans oversee the ticketing process. State statutes and collective bargaining agreements also influence the amount of oversight required and whether it must be done by police officers; for example, the sys- tem used in Illinois checks the speeds of all vehicles, but a police officer in the enforcement vehicle must verify several details and approve issuance of a citation (Benekohal et al. 2009, 2010; Chitturi et al. 2010). In Saskatchewan, a private security con- tractor (typically a retired police officer) decides which vehicles are potential violators and activates the system to check the speeds of those individual vehicles; if a violation is observed the automation handles the process of sending a violation notice to the registered owner of the vehicle (Saskatchewan MOJ 2012; M. Muhr, Saskatchewan MOJ, personal communications, 2014). In most systems, a human operator verifies the license plate number determined by the automated system, which mini- mizes the risk of mis-reads of similar looking characters on the plate (such as B-8, D-O-0, I-1, and S-5). In some jurisdictions, the operator or officer also compares an image of the vehicle driver with the license photo for the vehicle’s registered owner and issues a citation only if they match. What is clearly different from human enforcement is that violation notices are sent by mail, so there is no need to chase or intercept speeders. AUTOMATED ENFORCEMENT TECHNOLOGIES Currently two technical approaches are in use for automated speed enforcement: 1. Single-point method. This method is based on an obser- vation of the vehicle’s speed at a single location. Radar units or similar speed detectors are integrated with the license plate recognition camera and the vehicle’s speed at the precise location of the camera is used to determine whether to issue a citation (or warning). 2. Point-to-point (average speed) method. This method uses two (or more) cameras spaced a known distance apart (Figure 36). A vehicle’s license plate is identified at the first camera (e.g., at the beginning of a work zone) and the plate is then re-identified downstream (e.g., at the end of a work zone). The time differential between the obser- vations allows the computation of the vehicle’s average speed over the monitored segment. Consequently, each driver is required to observe the speed limit throughout the entire segment, not just in the immediate vicinity of the cameras. Another characteristic of this method is that minor exceedances [such as briefly exceeding the speed limit while overtaking (passing) a slow vehicle] are not likely to generate a citation if the overall average speed remains below the limit. ASE, using the point-to-point (average speed) method, has been found to be one of the most effective ways to reduce speeds in work zones and on ordinary highway segments. An in-depth 2012 study conducted for Austroads (the Australian equivalent of AASHTO) reviewed the use of point-to-point ASE in Australia and internationally and made the following statements (Soole et al. 2012): In England, point-to-point speed enforcement . . . is now widely used. The first full implementation of the technology occurred in Nottinghamshire in July 2000. The program has expanded into urban areas more recently. Over 210 temporary systems have been operated in major road work schemes as well as 36 perma- nent installations by one provider and up to 40 temporary systems at road work sites by another provider. Evaluations of point-to-point systems have typically reported substantial reductions in mean and 85th percentile speeds associ- ated with the introduction of the technology. Moreover, average (and often even 85th percentile) speeds are reduced to at or below the posted speed limit. Such impacts have been reported in asso- ciation with both permanent and temporary systems employed in various countries throughout the world. Exceptional rates of Point-to-Point Speed Enforcement compliance with posted speed limits are also noted, with offence rates typically reported to be less than 1%, even when daily traffic volume is high. Further, the proportion of vehicles exceeding the speed limit is often found to be drastically reduced (upwards of a 90% reduction) and the approach has been noted as particularly effective in reducing excessive speeding behavior. Reductions in all crash types, par- ticularly fatal and serious injury crashes, have been reported. The single-point ASE method has been shown to be advan- tageous in terms of speed limit compliance and safety. As with

59 In work zones there are additional constraints on tradi- tional enforcement techniques, which sometimes render active enforcement infeasible: • Physical space to park the police vehicle while waiting for violators may be limited. • Acceleration distance may be insufficient for the police vehicle to enter the traffic stream safely after a violator has been detected. • The vehicle that is being stopped for speeding may have difficulty finding an appropriate place to pull over. • Deceleration distance may be limited, resulting in reduced traffic flow as the speeder searches for a place to pull over. This is especially likely in work zones where only one lane is open to traffic. • Roadway and shoulder width may be insufficient to park the two vehicles while investigating the violation and preparing the citation. In some cases, this may pose a safety hazard; for example, the investigating officer may be required to stand very close to live traffic. • After the citation process is completed, acceleration distance for the vehicles to re-enter the traffic stream may be problematic from a safety and/or capacity perspective. Interviews with the state DOT officials revealed concerns that the effectiveness of police presence diminishes once an officer has initiated a traffic stop, because little or no action can be taken against other speeders. As a result, some jurisdictions have transitioned from traditional one-on-one enforcement to multi-officer techniques, which require still more labor. ASE addresses many of the limitations described earlier. Its legal status varies widely from state to state; in some states, it is expressly permitted through a statutory provision, in others it is expressly prohibited. Some states allow automated enforcement in certain situations, such as work zones or school zones, or when authorized by a municipal ordinance. In some cases, no statutory provision exists, yet case law indicates that ASE is being used. Finally, several states have no legislation addressing this topic, leaving the status of automated enforce- ment unclear. According to information compiled by NHTSA, as of February 1, 2010, 13 states, the District of Columbia, and Puerto Rico have legislation permitting the use of ASE to some degree (NHTSA 2011). An additional three states utilize ASE without explicit legislation or case law. Sixteen states explicitly prohibit the use of ASE, whereas 18 states do not address this issue legislatively. Arizona legislation repealed the statute establishing the Photo Enforcement Fund, effective July 2012 (CTC & Associates 2011). According to informa- tion compiled by the Insurance Institute for Highway Safety, 132 localities in the United States had ASE programs and four states were using speed cameras statewide in work zones as of May 2014 (IIHS 2014). The Province of Quebec appears poised to become the first North American jurisdiction to make widespread use of ASE, with 24 photo radar units to be acquired in 2014 and a “larger number” in 2015 (MTQ 2014). traditional “human” enforcement, single-point ASE results in a moderate reduction in work zone capacity; for exam- ple, using a four-regime traffic flow model, an Illinois study found that single-point ASE reduced work zone capacity by 100 passenger cars per hour per lane (pce/h/ln) (Avrenli et al. 2012). European experience indicates that ASE using the point- to-point method (average speed) is beneficial in terms of speed limit compliance, crash reduction, work zone capacity, and fuel consumption and emissions (Soole et al. 2012): [International] evaluation results generally indicate a decreasing trend in KSI (killed or serious injury) crashes after the installation of point-to-point speed enforcement in the order of between 33 [and] 85%. Reductions in minor injury crashes were also noted. However, statistical significance testing, the control of confounding factors (including regression-to-the-mean) and the use of control/ comparison areas, were absent from all these evaluations. An additional benefit associated with point-to-point speed enforcement is more homogenized traffic flow and increased traf- fic capacity resulting from reduced vehicle speed variability and subsequent increased headway. . . . [Single-point enforcement] cameras have been found to be associated with a stop-start motion created by acceleration and braking close to camera sites and this has been shown to have a detrimental impact on traffic flow. . . . A number of . . . studies conducted in England, Scotland, the Nether- lands and France [provide] evidence of improved traffic flow [with point-to-point enforcement], generally as a result of reductions in the standard deviation in vehicle speed variation . . . Reduced congestion resulting from improved traffic flow due to less speed variation equates to higher volumes of traffic being able to travel through a stretch of road before traffic flow breakdown occurs. This increases the capacity of the existing road. HUMAN AND AUTOMATED ENFORCEMENT COMPARED Traditional traffic stops are labor-intensive: a police officer must identify a violator, pull the violator over, check the viola- tor’s driving record, and issue a warning or a citation. Although this one-on-one approach (one police officer working on one violator) is effective, its scope is inherently limited by the avail- able police human resources. FIGURE 36 British standard signs notifying drivers of point- speed (left) and average-speed (right) photo enforcement (Highways Agency 2006).

60 WORK ZONE AUTOMATED ENFORCEMENT IN THE UNITED STATES Illinois, Maryland, Oregon, and Washington State currently use automated work zone speed enforcement. Case Exam- ples 3, 4, and 5 elaborate on the use of ASE in each of the states and summarize findings about effectiveness. In most cases the point speed method is used. Typically, the system is based on a self-contained vehicle that has been equipped to identify vehicles traveling at a speed above a certain thresh- old, capture image(s) of the vehicle’s license plate, and in some cases capture an image of the driver. The images usually include date, time, location, and speed information. Typically, the vehicles are manned by police officers and the decision to issue citations is made by the police officers. Research has shown that ASE has limited spatial effect at locations downstream of the ASE vehicle (Medina et al. 2009; Lodes and Benekohal 2013). Medina et al. compared the average speeds of vehicles at the ASE location and 1.5 miles downstream. ASE reduced the average speed of free-flowing vehicles by 2 to 3.8 mph for cars and by 0.8 to 5.3 mph for trucks. Lodes and Benekohal (2013) also compared the speeds of individual drivers near ASE and 1.5 miles downstream; paired data were used to quantify the speed change behavior and spatial effect of the treatments. Approximately 85% of drivers sped up after passing the ASE vehicle, indicating that the spatial effectiveness of point-speed-based ASE is limited. ESTABLISHING AUTOMATED SPEED ENFORCEMENT PROGRAMS A British document, Speed Limit Enforcement at Road Works: Guidance and Best Practice, published in 2006 by the High- ways Agency addresses site selection, design, implementation, and maintenance of automated work zone speed enforcement sites, as well as decommissioning of the site when the road work is complete (Highways Agency 2006). A flowchart for deciding when to use automated work zone enforcement is reproduced in Figure 37. The document recommends publiciz- ing the planned use of speed cameras starting 4 weeks before deployment at each project site and notes that the “publicity campaign should emphasize that cameras are there to protect [the] workforce.” The project manager is also advised to pre- pare an “evidence pack” documenting the site layout, signage, and daily equipment checks, which can be used if a driver challenges a citation issued through the system. Although political opposition to automated enforcement can be “vociferous” (Pilkington and Kinra 2005), polls repeatedly show that a majority of the public responds pos- itively to ASE. The extent of support varies widely, from 77% in Scottsdale, Arizona, to 51% in Washington D.C. (CTC & Associates 2011). A 1998 NHTSA survey identified invasion of privacy (26%), preference for in-person contact with an officer (14%), and camera errors (12%) as the pri- mary public objections. International research suggests that AUTOMATED ENFORCEMENT AS A HIGHWAY SAFETY METHOD Although no U.S. research has been found evaluating the safety benefits of ASE in work zones, other research has shown that in general ASE has safety benefits. Thomas et al. (2008) performed a critical review of 90 studies from 16 countries and identified 13 that satisfied the methodological review crite- ria. They estimated that injury crash reduction in the range of 20% to 25% is reasonable for site-specific safety benefit from conspicuous fixed-camera ASE locations. A similar meta- analysis prepared in 2005 found that all 14 observational studies meeting the study’s inclusion criteria reported a reduction in road traffic collisions and casualties (Pilking- ton and Kinra 2005). The reduction in adverse outcomes in the immediate vicinity of camera sites varied considerably across studies, with ranges of 5% to 69% for collisions, 12% to 65% for injuries, and 17% to 71% for deaths at camera sites. Smaller reductions in adverse outcomes were seen over a wider area. Increased vehicle headway (i.e., greater spacing between vehicles) is a surrogate measure for improved safety: longer headway reduces the likelihood of rear-end crashes. A recent U.S. study examined headway and distributions of platoon- ing traffic with and without the presence of ASE in two work zones. Mean headways of cars in the median lane and trucks in the shoulder lane significantly increased when ASE was present (Wang et al. 2010). Although not specific to work zones, experience in France associates considerable safety benefits with ASE. In November 2003, the first speed cameras were installed across the country. At the end of 2004, there were 400 speed cameras (232 fixed and 168 mobile), and by the late 2000s well over 2,000 devices were in operation (including fixed and mobile cameras). The penalty system was modified, with minor offences having fixed fines and more serious offences having greater fines. The enforcement process is now fully automated: a citation is sent automatically to the vehicle owner who must pay it within 45 days. After paying the fine it is possible to designate another driver as the offender, which has reduced the appeal rate to less than 1%. Overall detection rates have increased and sanctions are more severe for repeat offenders. The average speed on French roads decreased by 5 km/h (3 mph) over three years. The rate of “excessive speeding” [defined as more than 30 km/h (18.6 mph) over the limit] was reduced by a factor of five. Very favorable safety outcomes have been reported, including a 40% to 65% decrease in fatal crashes in the vicin- ity (6 km, approximately 3.7 miles) of fixed cameras. Between 2002 and 2005, fatalities decreased by more than 30% in France—an unprecedented result. These substantial decreases are not entirely the result of the implementation of automatic speed controls; however, it is estimated that the decrease in speed, in which automatic speed control played the major role, accounted for roughly 75% of this decrease (OECD 2006; Howard et al. 2008; Zarei et al. 2009).

61 Confirm requirements for camera equipment and servicing to Enforcement Authority Guidance for the use of TASCAR to reinforce temporary speed limits on Motorways and Trunk Roads Are roadworks Major Works? Is planned duration of Major Works TM 20 days or more Are Enforcement Authority, HA and Designer content that TASCAR is not to be used? Is number of visits to move cameras more than 10% of road works TM days? Are HA Project Sponsor, MAC and Designer content that TASCAR is not to be used? Is TASCAR recommended as a result of the risk assessment Does Enforcement Authority support proposal for TASCAR? Does HA Project Sponsor support proposal for TASCAR? Does HA Route Manager ratify decision NOT to install TASCAR? TASCAR not to be used on site TASCAR installed and operated on site Determine type, number and location of cameras and signing in conjunction with Enforcement Authority and produce estimated cost. Establish whether Enforcement Authority or HA will be responsible for provision of equipment. Carry out risk assessment to determine if TASCAR is appropriate. Consider factors such as road alignment, type of TM, proximity of traffic to workforce, safe position for installation and servicing of cameras and safety of all road users. Discussions to include Enforcement Authority, Designer, MAC and HA Project Sponsor. Approach Enforcement Authority through HA in first instance. Temporary Automatic Speed Cameras At Road works TASCAR may utilise Any combination of spot Speed or time over distance eqpt provided It is type approved eg GATSO and SPECS Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No FIGURE 37 Decision-making flowchart for Temporary Speed Cameras at Roadworks (TASCAR) published by the British Highways Agency in the context of overall traffic management (Highways Agency 2006).

62 Case Example 3: Automated Speed Enforcement in Illinois In 2006, Illinois became the first U.S. state to implement ASE in work zones. The state’s deployment has been evaluated in depth and described in considerable detail in the academic literature. The implementation of ASE was prompted by work zone safety con- cerns: fatalities in Illinois work zones increased to 46 in 2003 from 31 in 2002. Illinois introduced double work zone fines for speeding and enacted the Automated Traffic Control Systems in Construc- tion or Maintenance Zones Act, which authorized the use of cam- eras by the state police to enforce speed limits. The Act requires that construction workers be present when ASE is in use. It allows ASE to be used day or night, even if the workers are behind temporary concrete barriers. The law also requires special signs (Figure 38a) to be posted to inform motorists of ASE in the work zones. ASE began with a pilot program of two vans; as of May 2014, five vans were in use during the construction season (usually April–October), with deployment limited to freeway work zones. Each DOT district was allocated a budget for automated enforce- ment, with the enforcement locations subject to approval by the agency’s central office (P. Lorton, personal communication, 2014). Illinois DOT uses a self-contained ASE van (shown in Figure 38b) provided by a private vendor. As shown in Figures 38b and c, each ASE van is equipped with two radar units that monitor the speed of approaching vehicles. One unit is called the down-the-road radar and the other across-the-road radar. • The speed obtained using the down-the-road radar is displayed on a large LED sign mounted on top of the van, providing point-to-point ASE is perceived to be fairer than single-point techniques because drivers are less likely to be cited for instantaneous, inadvertent speeding (Soole et al. 2012). General guidance on establishing automated speed enforce- ment programs has been published by NHTSA (2008) and in NCHRP Report 729 (Eccles et al. 2012); the latter also addresses the start-up of automated systems to reduce red light running. Detailed case examples for four cities with successful automated enforcement programs are included in the NCHRP report, along with a comprehensive review of ongoing and terminated programs. The NCHRP Report 729 guidelines recommend that for a program to be successful it should be open to the public, be motivated by safety concerns, have strong enabling legisla- tion, and be repeatable. Similarly, a report prepared by the Organization for Economic Co-operation & Development (OECD) states that, “A crucial element for the success of the speed camera program is to have a transparent communica- tion on the allocation of the revenues [from fines] which are mainly invested on road safety improvements” (OECD 2006). This is consistent with social science research suggesting that cooperation decreases if a punishment is seen as simply serv- ing the self-interest of the punisher, and cooperation increases if incentives are seen as genuine tools to promote collective interests (Balliet et al. 2011). Down the Road Radar Across the Road Radar Down the Road Radar Enforcement Radar (a) (b) (c) FIGURE 38 Illinois ASE signs, vehicle, and operation: (a) special signs to be posted in work zones when ASE is deployed, (b) ASE vehicle, and (c) operation of ASE.

63 warning system (if installed) to warn the workers in the work area of an arriving speeding vehicle. Issuance of a speeding citation is at the discretion of the officer in the van and is generally limited to clear cases of excessive speed. A sample citation is shown in Figure 40. Currently, the viola- tion is tied to the driver of the vehicle. The vehicle’s owner is identified based on the speeding vehicle’s license plate, and the image of the person driving the speeding vehicle is compared with the vehicle owner’s photo from the driver’s license database. The ticket is approved by the police officer if the two images match. The vendor processes the approved citation and mails it to the registered owner of the vehicle within 14 days. Local stake- holders are proposing legislative changes so that citations can be issued even when the registered owner is not the speeding driver. Car rental companies are sent an Affidavit of Non-Liability and are required to respond within 30 days. Illinois fines for speeding in a construction or maintenance work zone are the same regardless of method of enforcement. As of May 2014, the minimum fine was $375 for the first offense and $1,000 for the second offense; if the second offense is within two years of the first offense, the driver’s license is suspended speeding drivers with a last chance to reduce speed and comply with the speed limit. The range of the down-the-road radar is approximately ¼ to ½ mile. • The across-the-road radar measures the speeds of vehicles when they are approximately 150 ft upstream of the van. The across-the-road radar operates at a specified angle to the path of vehicles and accounts for the angle effect. The operation of this ASE van is shown in Figure 38c. If the vehicle speed measured by the across-the-road radar is greater than a specified value, the radar activates the two on-board cameras to photograph the vehicle. The rear camera (Figure 39a) captures the driver’s face, while the front camera (Figure 39b) captures the vio- lator’s rear license plate. Each image is overlaid with the date and time of the violation. For night operation, the rear of the van is equipped with a flash unit (Figure 39d ) to illuminate the car and driver; the van’s headlights provide sufficient light to identify the violator’s license plate. The vans are staffed by specially trained Illinois State Police officers. The officers at the deployment station (Figure 39c) receive an audible alert of an approaching speeder and can see the speed- ing vehicle on a computer monitor. The officer can activate a (a) (b) (c) (d) FIGURE 39 Inside and outside ASE van: (a) rear camera, (b) front camera, (c) deployment station, and (d) flash unit at rear of van.

64 show that ASE is very effective in improving speed limit compli- ance in work zones. References: (Benekohal et al. 2008, 2009a, b, 2010; Hajbabaie et al. 2008, 2011; Chitturi et al. 2010; Wang et al. 2011; Lodes and Benekohal 2013). Case Example 4: Automated Speed Enforcement in Maryland In October 2009, the Maryland State Highway Administration began a work zone ASE pilot called Maryland SafeZones. It has since become a permanent part of the state’s work zone enforce- ment activities. Speed cameras are mounted on sport utility vehicles (SUVs) and can be located in work zones on expressways and con- trolled access highways with a speed limit of 45 mph or greater. The system uses Lidar to ensure that the speeds measured are of individual vehicles. Maryland does not require workers to be present for citations to be issued. As in Illinois, special signs (see Figure 41) informing drivers of ASE are required. Trailer-mounted speed display signs are used to notify drivers of their speed. The SUVs are oper- ated by trained operators; however, the Maryland State Police review all violations (exceeding the speed limit by 12 mph or more) before citations are issued. Civil infraction fines are $40 and no points are for 90 days (IDOT 2014b). A portion of the revenue collected from the fines is used to pay off-duty state troopers who pro- vide additional enforcement in work zones. The equipment ven- dor receives a processing fee of $15 per ticket in addition to contractual fees of $2,950 per month per van for provisioning and maintenance of the van, associated equipment, and police officer training. ASE in Illinois work zones has been extensively evaluated by university researchers. Three speed datasets were collected at two work zones in Illinois to study their effectiveness. In all but one sce- nario, the average speed was significantly lower than the work zone speed limit of 55 mph when ASE was present in the work zone. ASE reduced the work zone speeds of cars and heavy vehicles by 3 to 8 mph. The percentage of vehicles exceeding the speed limit was drastically reduced; after treatment, the vast majority of speeding vehicles exceeded the speed limit by fewer than 5 mph. In one work zone, only about 2% of cars exceeded the speed limit by more than 10 mph. As with cars, most of the speeding heavy vehicles were within 5 mph of the work zone speed limit; only a small percent- age exceeded the speed limit by 5 to 10 mph and only one heavy vehicle exceeded it by more than 10 mph. ASE had limited spatial effect downstream of the ASE vehicle. Overall, the Illinois studies FIGURE 40 Sample citation.

65 assessed against the driver’s license. As of July 2011, Maryland had seven ASE units that rotate through a series of work zones. Several factors such as work zone characteristics, speed limit, and avail- ability of traditional enforcement are considered in deciding where to deploy ASE. The Maryland SafeZones website (www.safezones. maryland.gov) provides the public with a regularly updated list of the work zones that are using ASE; as of May 2014, the system was potentially present at 17 sites. Franz and Chang (2011) studied the spatial and temporal effects of ASE on motorists’ speed behavior in Maryland. Data were col- lected at three work zones before, during, and after ASE at up to four locations: 2 miles upstream of ASE, at ASE, 0.5 to 1 mile downstream, and 1 to 2 miles downstream of ASE. ASE was found to reduce speeds of aggressive motorists and it created a more stable spatial speed distribution through the work zone. The data also sug- gest that motorists may learn the location of the ASEs and adjust their speeds accordingly. As illustrated in Figure 42, Maryland is not secretive about the locations of the ASE: the sites where it is in use are posted on an official website. Case Example 5: Automated Speed Enforcement in Washington State and Oregon In 2007, the state of Washington authorized a pilot program to use ASE in work zones when workers are present. Following the pilot evaluations, the state’s legislature authorized the use of ASE FIGURE 41 Signs notifying drivers of ASE in Maryland (Maryland State Highway Administration). FIGURE 42 Screenshot of Maryland SafeZones website showing current locations of ASE.

66 tion. The registered owner of the vehicle receives a $137 citation within 14 days of the violation. Revenue from the fine is shared, with $32 going to the Patrol’s highway account and the remainder deposited with the county where the violation occurred. Washington State DOT launched a pilot project in September 2008 to test the use of ASE in highway work zones; data were col- lected at two work zones. At one of the work zones, the number of drivers exceeding speed limit by more than 10 mph was reduced from 18% to between 8% and 13%. The number of drivers com- plying with the 60 mph work zone speed limit increased when ASE was present. The average speed was reduced by 2 to 3 mph (from 62 mph to 59–60 mph) for the northbound and southbound traf- fic, respectively. In 2007, Oregon’s legislature authorized the use of ASE in work zones on non-interstate state highways when workers are present. Signs notify drivers of the use of ASE. Normally citations are $160 or more depending on the violation, but double in work zones. The first project to use ASE in work zones in Oregon was in northwest Portland in 2009 at a site with a 40 mph posted speed limit. A sub- stantial impact of ASE on speeding was found: the average reduc- tion was 23.7% in vehicles traveling faster than 45 mph (Joerger 2010). Since then, ASE has only been used in one other project, in east Portland in 2013. The limited use of ASE in Oregon is in part attributable to cost considerations arising from public employee labor contracts. in work zones permanently beginning in 2011. As in Illinois, signs notifying the use of ASE (see Figure 43) need to be present in work zones. Washington uses radar to measure vehicle speeds and a cam- era unit records the rear license plate of any speeding vehicles. The entire system is housed in a SUV as shown in Figure 44. Trained operators monitor the system and forward the violator information to the Washington State Patrol, which checks the vehicle registra- FIGURE 43 Signs notifying drivers of ASE in Washington. FIGURE 44 Washington ASE implementation (Washington State DOT 2009).