2.4.1 Marking Material
There are a number of different materials used for marking crosswalks, including paint (waterborne or oil-based), epoxy, poly urea, thermoplastic and preformed tape. Transportation agencies weigh several factors when determining which marking material is most appropriate including costs, durability, reflectivity, friction coefficient (avoiding slip hazards) and whether or not the material can be applied using city labor and equipment. Thermoplastic is the crosswalk marking material most favored by those communities that were contacted. Paint is also frequently used, particularly on existing roads or where there is an immediate need. Epoxy was also mentioned by a number of communities. Thermoplastic and epoxy markings are used most often on repaving projects. Those communities that use paint markings typically use city crews and equipment to do the work while thermoplastic marking is more typically contracted out. At least one community mentioned the use of cold plastic in-lays for federal projects. Several communities mentioned using recessed thermoplastic to avoid plow damage and another community mentioned using this marking technique where there are a high number of turning movements, particularly by large vehicles.
Only a few communities mentioned that they have had slip hazard issues with crosswalk markings. Several strategies were mentioned for reducing slip hazards associated with thermoplastic. One community mentioned using the British Pendulum method to determine appropriate friction coefficient to avoid slip hazards. The same community mentioned that having the right conditions for the thermoplastic curing process was an important factor for avoiding slippery markings. It was also noted by several communities that newer thermoplastic mixtures contain sand or other coarse materials for reducing slip hazards. Bricks and stamped concrete were noted by at least two communities as creating hazards for bicyclists.
2.4.2 Strategies for Maintaining Crosswalks
When asked what special treatments or strategies are used for maintaining crosswalks, the majority of communities indicated that they did not have any special techniques for reducing maintenance. Some notable exceptions include spraying streets with primer to reduce salt damage, spacing crosswalk bars so they are generally out of the tire path, using pre-form thermoplastic in high-traffic areas and using different types of markings for different types of roadway surfaces, e.g. thermoplastic on concrete and poly urea on asphalt.
Thermoplastic is preferred in many cases due to the longevity of the material, however the initial cost and time requirements for installation are greater than paint. Snowplow damage was sighted as a common maintenance issue with the use of thermoplastic markings. Several communities have found that recessing thermoplastic markings decreases the likelihood of snowplow damage however; the practice is expensive and may require additional resources, especially if grinding concrete is necessary.
One community noted that they are beginning to see a clear correlation between traffic volumes and when maintenance of pavement markings, including crosswalk markings, is needed. This has allowed them to reduce inspection efforts. It was also noted that turning vehicles case significantly more wear of pavement markings, and locating markings out of turning areas, when possible, can reduce maintenance.
A common strategy to pay for the more expensive, but longer-lasting markings is to include the marking application within the initial construction, reconstruction or pavement replacement project. In most cases, the costs for these markings are covered by the project budget and not the maintenance budget. Maintenance budgets tend to be tight, whereas including even more expensive marking materials in a project, represent a small part of a larger construction budget.
It should also be noted that crosswalk maintenance should include the actual street surface, and not simply the pavement markings. Although crosswalks are a part of the roadway, they require a higher level of maintenance than surrounding roadway because pedestrians are less tolerant of defects than motorists. A minor pothole may not present an issue for most motorists, but can present a significant hazard for pedestrians. Surface defects in crosswalks should be noted when crosswalks are inspected or remarked, and repairs should be completed quickly.
Unit costs for various crosswalk marking materials vary considerably across the country. A National Cooperative Highway Research Program (NCHRP) Synthesis 306: Long-Term Pavement Marking Practices provides cost comparisons and a life-cycle-cost table. In general, thermoplastics provide a life of two to three times that of paint for long lines, however, costs averaged almost five times that of paint (epoxy markings had a life of two to three times that of paint, but had a cost of four times that of paint). Thus, when life-cycle-cost was calculated, paint was half the cost of thermoplastic. It is important to note that costs and durability ranged significantly in this study. There is a clear trade-off between the durability of thermoplastic and the lower costs of paint. Communities that use paint to mark crosswalks indicated that they must repaint crosswalks two to four times per year, whereas thermoplastic markings typically last 2 to 3 years.
Table 8 displays characteristics of four common crosswalk marking materials. It should be noted that costs vary widely across the country (see §2.4.3), and the ranges provided are approximate. Similarly, material lifespans are strongly impacted by the volume of traffic passing over the marking, and the use of snowplows on streets. Thermoplastic and preformed tape may not be appropriate in areas using snowplows unless the marking are inlaid in the pavement, which makes it less likely that a plow blade will pull the material off the street.
|Paint||$0.03 – $0.05/LF||9 – 36||Low|
|Epoxy Paint||$0.20 – $0.30/LF||48||Medium|
|Themoplastic||$0.19 – $0.26/LF||72*||Medium|
|Preformed Tape||$1.50 – $2.65/LF||48 – 96*||High|
Note 1: Thermoplastic and tape have shortened lifespans in snowy areas where they are often damaged by snowplows
Note 2: Inlaid thermoplastic or preformed tape may last significantly longer than standard surface applications
When considering the cost of crosswalk marking materials, it is important to consider the expected lifespan of one product versus another. Additionally, it is critical to take into account the cost of altering traffic patterns when markings must be redone. Products that may be more expensive up front may actually be less expensive over time if they need to be replaced less frequently. It is recommended that agencies perform lifecycle cost anaylsis for different materials based on their local product costs, labor costs, the cost of diverting traffic, and real-world observations of product lifespans given local maintenance conditions.
2.5 Pedestrian Signals
All communities that were contacted indicated that they have either switched out all their signals for LED countdown signals, or are in the process of doing so. Newer LED lights are highly rated by communities in terms of durability. Some cold-weather communities have noted that LED-based pedestrian and vehicle signals do not generate nearly as much heat as incandescent signals, and therefore do not melt off accumulated snow and/or ice as readily as incandescent systems.
2.5.1 Maintenance Issues and Response Time
Almost all communities that were contacted indicated that they have had few issues with their pedestrian signals. The term "durable" was used frequently. Several communities indicated that repairs are mostly due to damage from crashes. Most communities indicated that pedestrian signal repair is a high priority. Response times for repairs range from several hours to two weeks with the majority of communities reporting that they have signals fixed within one to two days.
At least two communities indicated having some issues with push buttons for pedestrian signals. In one community it was mentioned that the push buttons have been difficult to replace while another community mentioned that the buttons tend to stick once they receive some wear. If a community has a sidewalk inspection program, push button signal actuators should be inspected for functionality at the same time as adjacent sidewalks. Pedestrian signals should also be inspected at the same time as vehicular signal heads at the same intersection.
NCHRP Project 3-62 produced the document Accessible Pedestrian Signals: A Guide to Best Practices which includes the following statements about accessible pedestrian signal maintenance:
As with complex devices, APS have many features that may malfunction or fail in the course of its operation. If features such as WALK indication, locator tone, or signal interaction fail to work correctly, the resulting lack of information or misinformation for pedestrians who are blind can be dangerous. It is important that municipalities who have taken steps to install these devices also take steps to ensure correct functioning through the years.
The overseeing agency should conduct an audit or checkup of APS installations on a regular basis. Checkups should be conducted frequently if factors such as harsh weather may have affected the devices. At a minimum, APS should be inspected:
- Every 6 months
- After repairs to the intersection signals, poles or controller
- After changes to signal timing
The Guide also outlines repair issues after a crash damages signals and lessons learned from APS installations around the country.22
22 Harkey, David et al. Accessible Pedestrian Signals: A Guide to Best Practices. NCHRP Web-Only Document 117A. June 2007. http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_w117a.pdf.