Exit numbers in the United States

Main article: Exit number

In the United States, exit numbers are assigned to freeway junctions, and are usually numbered as exits from freeways. Exit numbers generally are found above the destinations (and route number(s) ) of the exit, as well as a sign in the gore. Exit numbers typically reset at political borders such as state lines. Some major streets also use exit numbers. Freeway exits in the United States are usually numbered in two formats: distance-based and sequential.

Interstate Highways

An example of an green exit number plaque for two exits at the same interchange
An example of a green exit number plaque for a left exit with a yellow "left" panel
Old mile tabs on Interstate 295 in Rhode Island; several other states did this. As of September 2007, these signs have been replaced and use only the sequential exit number scheme
Mile-based exit numbers on Interstate 4 in Volusia County, Florida. In this case, mile-based exits 111A and 111B had been sequential exits 53CA and 53CB, as the 'OLD 53CA' tab shows.
Kilometer-based exit numbers on Interstate 19 in Arizona

The Federal Highway Administration (FHWA) generally requires exit numbers (mile-based or consecutively) on the Interstate Highway System; the FHWA established that requirement in 1970.[1] The Manual of Uniform Traffic Control Devices (MUTCD) encouraged use of mileposts and exit numbering by 1961. The MUTCD mandated exit numbering in 1971.[1] The FHWA granted California an exception due to the cost of installing and maintaining additional signage. California was able to obtain a waiver because it had already built most of its freeways, although some freeways in Los Angeles County received junction numbers: Interstate 10 was the only freeway in the county that had a complete set of junction numbers. Interstate 5, US 101, and then CA 11 (now I-110/CA 110) were numbered for short distances from downtown Los Angeles. Freeway connections were unnumbered, and junction numbers were only shown on plates, not on gore signs. In 2002, the Cal-NExUS program began to completely number California's junctions.[2] The program is not well-funded, especially because of California's budget woes, so exits are only being signed with numbers when signs need to be replaced. As the efficiency of an exit numbering system for navigational purposes depends on all exits being consistently numbered, the usefulness of the system while only some exits are numbered is limited. Originally, the initial completion date for this project was set as November 2004. The deadline was then extended to 2008. However, the 2006 edition of the California MUTCD removed any sort of compliance deadline for the exit numbers.[3]

Nine states as of June 2008 and the District of Columbia use sequential numbering schemes on at least one highway, although the 2009 edition of the Manual on Uniform Traffic Control Devices (MUTCD) requires these jurisdictions to transition to distance-based numbering. Although a ten-year compliance period was proposed for the new edition of the MUTCD,[4] a compliance date for this change was ultimately not adopted with the 2009 edition, meaning that the transition is accomplished through a systematic upgrading of existing signing and there is no specific date by which the change must be implemented. However, the FHWA has required that all federally-funded routes with sequential numbering to adopt mileage-based exit numbers; the FHWA has required each state that currently uses sequential exit numbering to submit a plan to eventually transition to distance-based exit numbers.[5] Some of the states that currently have sequential numbering either have or intend to request a waiver from the Federal Highway Administration to retain their current numbering systems, while others have planned a gradual transition to mileage-based exit numbering over time as existing signage reaches the end of its serviceable life and is replaced. The mile-based requirement also mandates multiple exits in the same mile to use A, B, C, etc.; the "consecutive" numbering scheme (which must be phased out) for multi-directional interchanges sometimes uses N-S, or E-W.

Most states began with sequential numbers, while California numbered few exits during the 20th century:

Two highways (Interstate 19 in Arizona and Delaware Route 1) have metric numbering, because they were constructed during the time when the U.S. was thought to be completely converting to metric. Delaware Route 1 currently uses standard milepost (since 2003) when the metric-based posts were replaced, and several newer exit numbers (86, 91, 98) do not coincide with either the milemarker nor its kilometer conversion as they are offset by miles from a kilometer-based exit. I-19 currently has all exit numbers and distances in kilometers, but speed limits in miles per hour. The road has received funding for the distances to be changed back to miles.[18]

Other highways

Exit numbering on non-Interstate highways is less consistent. For example, Texas, which normally uses mile-based exit numbering, uses sequential numbering on U.S. Route 75 between downtown Dallas and the Oklahoma border. Similarly, the U.S. Route 54 freeway from El Paso to the New Mexico border also uses sequential exit numbering.

Early exit numbers

This transport-related list is incomplete; you can help by expanding it.

References

  1. 1 2 California Highways: Numbering Conventions – Postmiles. Accessed: 17 July 2008.
  2. Brown, Patricia Leigh. "Counting the way to San Jose." New York Times, 10 February 2002, sec. WK, p. 2.
  3. "California Highways: Numbering Conventions Exit Numbers". Retrieved 2009-03-05.
  4. Proposed Amendements to the MUTCD Section 2E.27 Lines 33–41
  5. MUTCD 2009 Edition Introduction, Paragraphs 22 through 24 and Table I-2
  6. Exit Numbering, www.kurumi.com, Accessed Nov 15, 2009
  7. I-395 Exit Re-Numbering Will Create Problems, Montville Patch, May 16, 2013
  8. Röckers Meet King Tubbys Inna Fire House Archived April 4, 2007, at the Wayback Machine.
  9. Upstate New York Roads – Interstate 890 Interchange Guide
  10. http://wpri.com/2016/03/29/ri-set-to-renumber-all-its-highway-exit-signs/
  11. Lozier, Marcia (January 3, 2014). "Caltrans tests reflective sheeting for guide-sign visibility and cost savings". Roads & Bridges. Retrieved October 8, 2015.
  12. Bid Results, Connecticut Department of Transportation, Accessed December 30, 2015
  13. Operations – Florida's Interstate Exit Numbers
  14. Georgia DOT – Interstate Exit Numbers
  15. "I-475 Exits To Conform To Mileposts". The Blade 138 (Toledo, Ohio). August 7, 1973. p. 17 via Google News Archive.
  16. "Turnpike interchange numbers start changing after Labor Day". The Bryan Times 54 (125) (Bryan, Ohio). May 28, 2002. p. 10 via Google News Archive.
  17. "Turnpike signs will be changing". The Bryan Times 54 (217) (Bryan, Ohio). September 14, 2002. p. 7 via Google News Archive.
  18. Holley, Denise (March 17, 2009). "New signs on Interstate 19 courtesy of recovery funds". Nogales International. Retrieved 2009-12-29.
  19. "Florida Department of Transportation Interchange Report" (PDF). Florida Department of Transportation. 2008-11-24. Retrieved 2009-07-27.
  20. 1 2 Patch, David (February 10, 2007). "ODOT extends numbered exits to noninterstates". The Blade 157 (41). p. B1. Archived from the original on February 10, 2007. Retrieved September 28, 2009.
  21. "Lorain County Photos: OH 2 through Lorain County". Roadfan.com.
  22. US 22 at Weirton Archived January 8, 2008, at the Wayback Machine.
  23. Wisconsin Department of Transportation. "Exit Numbers on Wisconsin's Freeways". Retrieved 2007-12-06.
  24. Merritt Parkway (CT 15)
  25. http://www.texasfreeway.com/Houston/historic/photos/images/i45_safety_barrier_july_1956.jpg

Further reading

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