Nada D Trout

Survey of State Law Enforcement Personnel on Work Zone Enforcement Practices

An important first step in maximizing the effectiveness of work zone law enforcement is to determine how officers operate. Although transportation professionals may understand the benefits of different enforcement strategies, does this translate to improved enforcement methods in the field? A survey was developed and administered to determine the problems encountered by various state law enforcement agencies when enforcing work zones. The survey was also an attempt to identify areas of improvement and innovative practices worthy of further development. State law enforcement agencies from 20 states were contacted by telephone to determine how work zones were enforced in their respective states. Officers were asked questions regarding funding for work zone enforcement; techniques used by law enforcement at work zones; locations in or near work zones where officers are typically stationed; the level of coordination between law enforcement, the state highway authority, and the construction contractor; and initiatives that helped maximize the effectiveness of law enforcement in work zones. A strategy identified in this research was the formation of specialized units to patrol work zones and to train other officers to effectively patrol work zones. A second strategy allows local law enforcement officers and retired officers the opportunity to enforce work zone practices on state roadways to overcome a chronic shortage of available officers.

EFFECT OF THE WORK ZONE DOUBLE-FINE LAW IN TEXAS

Results of research conducted to investigate the short-term effects of the double-fine law in work zones implemented in Texas on January 1, 1998, are presented. Field studies of traffic speeds in several work zones were performed before and after the law was implemented. Traffic citation data for these same work zones were also obtained from the Texas Department of Public Safety. Analyses showed that traffic speeds in the work zones 4 to 6 months after the law was enacted were essentially unchanged from before the law was enacted. Similarly, citation frequency and fines levied were not significantly higher than they were before enactment of the law. The data suggested that a higher proportion of drivers who were issued citations after the law was implemented chose to take defensive driving training and to have the ticket subsequently dismissed. However, researchers could not determine whether this was due to the increased fine or to other external reasons.

Accommodating Pedestrians with Visual Impairments In and Around Work Zones

Results are presented of a Texas Transportation Institute study that assessed how work-zone information can be related to visually impaired users through audio messages. Researchers conducted a two-phase study that included both a laboratory survey and a field test of audio messages presented through motion-activated recordings in a mock work zone. A few of the key points found during this effort are as follows: (a) it is critical that an alternate-route message clearly state that the path will lead the pedestrian to the sidewalk on the opposite side of the street; (b) critical message elements for navigation of alternate routes were the initial turning or crossing instruction and the distance that pedestrians would need to continue on that path; (c) the existence of a high number of driveways can affect the ability of the visually impaired to count the number of blocks they have traveled and should be considered when alternate routes are established; (d) overload of information is still a concern, but there are specific message elements or terms that appear to have a greater adverse impact on recall (e.g., the use of distances in feet) than the typical message loading considerations; and (e) when it is important to provide warning messages about features for the visually impaired walking through or near a work area, it is critical to state clearly that the path is available (i.e., “sidewalk is open”).

Motorist Comprehension of Traffic Control Devices for Mobile Operations

In 2004, researchers conducted surveys to evaluate motorist comprehension of various mobile traffic control devices used to inform drivers about the number of vehicles in a work convoy; speed differential between the work convoy and the normal traffic stream; and passing a work convoy on two-lane, two-way roadways with improved shoulders. Four static signs were investigated to ascertain whether they inform motorists that they are approaching multiple work vehicles. Three of the signs (including the sign “Work Convoy”) had comprehension levels less than 53%. Placing the number of work vehicles on the sign (i.e., “3 Vehicle Convey”) improved the comprehension level to 79%. Various mobile speed displays were evaluated to determine if they provide information to motorists about the speed differential between the work convoy and approaching traffic. Only the “Your Speed” display (indicating speed of approaching vehicles) was understood by more than 85% of participants. In Texas, when mobile operations are conducted on the centerline of a two-lane, two-way roadway with improved shoulders, motorists are directed via a right flashing arrow panel to pass the work convoy to the right on the improved shoulder. However, under the current setup, only 66% of participants understood that they were supposed to pass the work vehicles on the right. All alternative text messages improved the comprehension rate; however, the “Pass on Shoulder” message was understood by the highest percentage of participants, at 97%.

Red Retroreflective Raised Pavement Markings: Driver Understanding of Their Purpose

Research was conducted to evaluate drivers’ understanding of red retroreflective raised pavement markers (RRPMs) on two-lane and four-lane undivided and divided roadways. The study included 191 participants, equally divided between three participant groups: drivers from countries with left-hand drive (e.g., Australia, United Kingdom, and Japan), drivers from Hawaii, and drivers from the continental United States. Five typical roadway configurations were tested by means of a laptop survey. For each roadway configuration, standard pavement markings were shown as a baseline condition. Three alternate marking treatments were shown for each typical roadway configuration. Two of the alternative marking treatments consisted of different combinations of supplemental RRPMs, and the third alternative treatment consisted of supplemental pavement marking arrows without RRPMs. The general findings were that red RRPMs on one-way divided roadways to indicate the wrong direction of travel helped drivers realize when they were going in the wrong direction; red RRPMs on undivided roadways can improve understanding of drivers from countries with left-hand drive without reducing the understanding of drivers from Hawaii and the continental United States; and replacing supplemental RRPMs with supplemental arrows always improved the rates of correct responses for all roadway configurations and for all participant groups.

Devices to Implement Short-Term Speed Limits in Texas Work Zones

In Texas, speed limits for short-term (less than 12 consecutive h) work zones are used when workers or equipment are not behind a concrete barrier, work activity is within 15 ft of the pavement edge, or work is actually occurring on the pavement. In these situations, speed limit signs for short-term work zones should be posted and visible to the motorists only when work activity is present and covered or removed when no work activity is present. Covering or removing signs can be a tedious task to complete daily or weekly. In addition, this task may interfere with normal traffic flow and expose workers to traffic hazards. Some contractors choose not to cover or remove signs; others simply forget: thus speed limits for short-term regulatory work zones extend into time periods with no apparent need for a speed limit reduction. New sign technologies may simplify the implementation process speed limits for short-term work zones and could enhance the use of such speed limits in general. However, such technologies have not been used extensively for speed limits in work zones in Texas. Thus, researchers at the Texas Transportation Institute conducted field studies to determine the operational effectiveness of electronic speed limit signs and flexible roll-up speed limit for work zones signs. The researchers recommended the use of both types of signs.

Driver Comprehension of Messages on Truck-Mounted Changeable Message Signs During Mobile Maintenance Operations

Use of truck-mounted changeable message signs (TMCMSs) during mobile maintenance operations is desirable to provide drivers with information to better prepare them for unexpected conditions. Traditionally, temporary traffic control devices used during mobile operations have been limited to arrow boards and sometimes static warning messages mounted on a work vehicle. The use of warning signs in advance of an operation typically is not practical because of the constant movement and stop-and-go nature of the work. TMCMSs can fill an information gap for these mobile operations and provide drivers with better information about them, including actions to be expected. This paper describes the use of findings from a human factors laboratory study and basic message design principles to create a sampling of recommended messages for use on TMCMSs during mobile maintenance operations. These messages were defined by the type of work, road type, and the identified concerns to be addressed.

Guidelines for the Use of Pavement Marking Symbols at Freeway Interchanges

Pavement marking technology has advanced sufficiently to allow large multicolor symbols to be marked on the pavement. These symbols provide drivers with another source of information to help them make good navigation decisions. The objective of this research was to identify appropriate in-lane pavement marking characteristics for use near freeway interchanges. Two laptop-based surveys were conducted to evaluate driver comprehension, recognition time, and preference for different designs and applications. From the information obtained in these surveys, researchers developed the following recommendations for in-lane pavement markings near an interchange: (a) arrow and shield markings should be used in combination; (b) in simple single-lane exits (particularly traditional lane drop right exits), pavement marking symbols only need to be placed in the exit lane; (c) if in-lane pavement markings are used at complex interchanges (e.g., optional lanes, multilane exits), the markings should be applied to all lanes; (d) optional lane pavement markings should provide the same basic information as other lanes at that interchange (i.e., show both highway shields and an option arrow); (e) lane markings should not be staggered; (f) when all symbols are the same, they should be installed in a single line; and (g) the use of cardinal directions should be limited.