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Out of town bypasses

Health Factors: Community Safety Housing & Transit
Decision Makers: Community Development Professionals Local Government State Government
Evidence Rating: Some Evidence
Population Reach: 20-49% of WI's population
Impact on Disparities: No impact on disparities likely

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Out of town bypasses are roads that avoid built-up areas such as towns, cities, or commercial/business districts. Bypasses are designed to reduce traffic congestion within the town or city.

Expected Beneficial Outcomes

Reduced injuries
Increased pedestrian and cyclist safety
Improved quality of life
Improved sense of community
Reduced emissions

Evidence of Effectiveness

There is some evidence that out of town bypasses decrease traffic injuries and increase pedestrian and cyclist safety (Egan 2003, Cena 2011, Elvik 2001, Thomson 2008). Additional evidence is needed to confirm effects.

Out of town bypasses have been shown to decrease injuries on both main roads through town and on bypass roads (Cena 2011, Elvik 2001, Thomson 2008). Out of town bypasses can also reduce noise levels, support community cohesion, improve overall quality of life in towns (Ramis 2003), and reduce particulate matter pollutants near the bypassed road (Burr 2004).

Bypasses are often located in less populated areas, since changing traffic flow may increase air pollution (Thomson 2008), noise levels, and decrease community cohesion near the bypass (Egan 2003, Thomson 2008). In some instances out of town bypasses may shift crash locations, modestly reducing the effect on overall crash rates (Elias 2011). 


United States

Bypass roads are found in urban areas throughout the US, although design and operational practices vary (US DOT-FHWA).


There are bypasses around a number of Wisconsin cities, examples include Fort Atkinson, Fond du Lac, Whitewater, and Oconomowoc (WI DOT-Transportation ready, WI DOT-US 151 bypass).

Citations - Evidence

Burr 2004 - Burr ML, Karani G, Davies B, Holmes BA, Williams KL. Effects on respiratory health of a reduction in air pollution from vehicle exhaust emissions. Occupational & Environmental Medicine. 2004;61(3):212-8. Accessed on November 27, 2015
Cena 2011 - Cena LG, Keren N, Li W, et al. A Bayesian assessment of the effect of highway bypasses in Iowa on crashes and crash rate. Journal of Safety Research. 2011;42(4):241–52. Accessed on December 1, 2015
Egan 2003* - Egan M, Petticrew M, Ogilvie D, Hamilton V. New roads and human health: A systematic review. American Journal of Public Health. 2003;93(9):1463-71. Accessed on December 22, 2015
Elias 2011* - Elias W, Shiftan Y. The safety impact of land use changes resulting from bypass road constructions. Journal of Transport Geography. 2011;19(6):1120–9. Accessed on January 14, 2016
Elvik 2001 - Elvik R, Amundsen FH, Hofset F. Road safety effects of bypasses. Transportation Research Record: Journal of the Transportation Research Board. 2001;1758(01):13–20. Accessed on January 12, 2016
Ramis 2003* - Ramis J, Alba J, Garcia D, Herna F. Noise effects of reducing traffic flow through a Spanish city. Applied Acoustics. 2003;64(3):343-64. Accessed on February 1, 2016
Thomson 2008 - Thomson H, Jepson R, Hurley F, Douglas M. Assessing the unintended health impacts of road transport policies and interventions: Translating research evidence for use in policy and practice. BMC Public Health. 2008;8:339. Accessed on November 9, 2015

Citations - Implementation

US DOT-FHWA - US Department of Transportation (US DOT). Federal Highway Administration (FHWA). Accessed on March 3, 2017
WI DOT-Transportation ready - Wisconsin Department of Transportation (WisDOT). Transportation ready reference. Accessed on November 18, 2015
WI DOT-US 151 bypass - Wisconsin Department of Transportation (WI DOT). US 151 bypass improvements: Project overview in Fond du Lac. Accessed on March 14, 2016

Page Last Updated

February 13, 2013

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