Route shield pavement markings for Interstate Highways 30 and 35E at the Dallas Horseshoe.
Route shield pavement markings for Interstate Highways 30 and 35E at the Dallas Horseshoe.

A route shield pavement marking (also called an advance pavement marking[1] or pavement marking shield[2]) is a road surface marking that depicts a route shield and functions as either a road traffic safety measure or a mitigation against street sign theft.

Purpose

Route shield pavement markings along Historic U.S. Route 66 in Amboy, California.
Route shield pavement markings along Historic U.S. Route 66 in Amboy, California.

In the United States, route shield pavement markings are closely associated with U.S. Route 66. Owing to the original route's fame, reassurance markers for "Historic U.S. Route 66" have often been stolen by souvenir hunters, so many localities have painted or stenciled the U.S. Route shield or outline directly onto the pavement.[3][4]

Route shield pavement markings Interstates 8 and 5 in San Diego.
Route shield pavement markings Interstates 8 and 5 in San Diego.

The 2009 edition of the Manual on Uniform Traffic Control Devices and accompanying Standard Highway Signs and Markings handbook introduced the route shield pavement marking as an option generally available to traffic engineers.[1] It may be used as a safety device on a multilane, controlled-access highway, reminding motorists to change to the correct lane well in advance of a major freeway interchange or fork; on a surface street leading to a freeway entrance ramp, where it is infeasible to install an overhead guide sign;[5] or ahead of a turbo roundabout.[6] Route shield pavement markings are intended to aid older drivers who have experienced a decline in working memory or attention span.[1]

Route shield pavement markings have been installed in a number of U.S. cities.[1] In 2018, the California Department of Transportation began installing them in the Sacramento area using funds from the 2017 Road Repair and Accountability Act.[7] In Knoxville, Tennessee, route shields were affixed to the Interstate 40 road surface as a cost-effective mitigation for a high crash rate caused by weaving maneuvers.[8]

The Ohio Department of Transportation suggests route shield pavement markings as one method for park and trail managers to display reassurance markers along off-road portions of U.S. Bicycle Routes and state bicycle routes.[9]

Design and application

Modern route shield pavement markings are made of thermoplastic road marking paint with glass beads for reflectivity at night. They may be installed as part of a routine resurfacing project or after the fact, by placing and melting prefabricated mats onto the road surface. Depending on traffic volumes and weather conditions, they are expected to last from three to five years.[5] The paint can be textured to provide adequate friction for motorcyclists.[8]

A route shield pavement marking measures approximately 6 by 15 feet (1.8 m × 4.6 m). It is half the width of a standard Interstate highway lane; like some other kinds of pavement markings, it is elongated to appear proportional to a driver traveling at high speed.[5][8] It may appear in full color or as a simple outline.[10]

Effectiveness

A 2010 study by the Texas A&M Transportation Institute found that route shield pavement markings combined with directional arrows were more effective than overhead guide signs in stressful situations.[8] As of 2019, their effectiveness has not been proven in the field through statistical analysis.[5]

References

  1. ^ a b c d Brewer, Marcus; Murillo, Debbie; Pate, Alan (June 2014). "Interchanges". Handbook for Designing Roadways for the Aging Population. Washington, D.C.: Federal Highway Administration. Retrieved June 26, 2021.
  2. ^ Signing and Marking Design Guidelines (PDF). Atlanta: Georgia Department of Transportation. October 29, 2020. p. 12-3. Retrieved July 3, 2021.
  3. ^ "Route 66 History". Route 66 World. Archived from the original on August 23, 2020. Retrieved November 18, 2014.
  4. ^ "Finding Your Way on Route 66". Route-66.tv. Archived from the original on December 30, 2014. Retrieved November 18, 2014.
  5. ^ a b c d "Route Signs Go Ground-Level" (PDF). Mile Marker. Sacramento, California: California Department of Transportation. Winter 2019.
  6. ^ "Marking". Manual on Uniform Traffic Control Devices. Dover, Delaware: Delaware Department of Transportation. December 2012. Retrieved June 26, 2021.
  7. ^ "Caltrans News Flash #185 - New SB 1 Funded Route Shields Improve Motorists Safety" (Press release). Sacramento, California: California Department of Transportation. November 2, 2018. Retrieved June 26, 2021.
  8. ^ a b c d Jacobs, Don (October 27, 2016). "Knox road shields guide I-40 drivers". Knoxville News Sentinel. Knoxville, Tennessee. Retrieved June 26, 2021.
  9. ^ "State & US Bike Route System Overview and Implementation" (PDF). Ohio Department of Transportation. May 8, 2019. p. 5. Retrieved July 7, 2021.
  10. ^ "Pavement and Curb Markings". Manual on Uniform Traffic Control Devices (2009 ed.). Washington, D.C.: Federal Highway Administration. May 2012. Retrieved June 26, 2021.

Further reading