Runaway truck ramp

Emergency escape ramps are usually located in mountainous areas which cause high construction costs and present difficult site selection.{{cite journal

| author = DOT Arizona |date=May–June 1993 | title = Full-Scale Arrester Bed Testing Leads to More Cost-Effective Design | journal = TR News | issue = 166 | pages = 20–21 | url = http://www.trb.org/publications/trnews/rpo/rpo.trn166.pdf | access-date = 2006-07-23}} Designs include:

• Arrester bed: a gravel-filled ramp adjacent to the road that uses rolling resistance to stop the vehicle. The required length of the bed depends on the mass and speed of the vehicle, the grade of the arrester bed, and the rolling resistance provided by the gravel. These are similar to gravel or sand traps used on motor racing circuits in runoff areas on road courses and drag strips.
• Gravity escape ramp: a long, upwardly inclined path parallel to the road. Substantial length is required. Control can be difficult for the driver; problems include rollback after the vehicle stops.
• Sand pile escape ramp: a short length of loosely piled sand. Problems include sudden, forceful deceleration; sand being affected by weather conditions (moisture and freezing); and vehicles vaulting and/or overturning after contacting the sand pile.
• Mechanical-arrestor escape ramp: a proprietary system of stainless-steel nets transversely spanning a paved ramp to engage and retard a runaway vehicle. Ramps of this type are typically shorter than gravity ramps, and can work even on a downhill grade.{{cite web | title = Highway 11 Runaway Truck Ramp | url = http://www.highway11northbay.com/ | publisher = Ontario Ministry of Transportation | date = 2009-06-26 | access-date = 2016-11-18 | archive-url = https://web.archive.org/web/20120506072004/http://www.highway11northbay.com/ | archive-date = 2012-05-06}} These systems tend to be costly, but may save expensive real estate in crowded areas and prevent even more costly crashes. One such ramp at Avon, Connecticut in the United States has an electrically heated pavement surface to prevent snow and ice accumulation.{{Cite web |url=http://www.4ishgd.valencia.upv.es/index_archivos/81.pdf |title=Archived copy |access-date=2011-12-17 |archive-date=2011-09-05 |archive-url=https://web.archive.org/web/20110905164049/http://www.4ishgd.valencia.upv.es/index_archivos/81.pdf |url-status=dead }}
• Alternatives: such as a vehicle arresting barrier.{{cite book | date = May 2006 | title = Design Manual - Auxiliary Lanes | publisher = Washington State Department of Transportation | pages = Chapter 1010, pp. 4–5 | url = http://www.wsdot.wa.gov/EESC/Design/DesignManual/desEnglish/1010-E.pdf | archive-url = https://web.archive.org/web/20050924192440/http://wsdot.wa.gov/EESC/Design/DesignManual/desEnglish/1010-E.pdf | url-status = dead | archive-date = 2005-09-24 | no-pp = true }}

Emergency escape ramps are usually located on steep, sustained grades, as in mountainous areas. Long descending grades can allow high vehicle speeds to be reached, and truck brakes can overheat and fail through extensive use. The ramps are often built before a critical change in the radius of curvature of the road, or before a place that may require the vehicle to stop, such as before an intersection in a populated area.

The placement criteria can vary from one region/country to another.

File:Runaway truck ramp east of Asheville, NC IMG 5217.JPG|Runaway ramp on Interstate 40 east of Asheville, North Carolina

File:Great Eastern Highway Truck Arrester Bed.JPG|An arrester bed on Great Eastern Highway in Western Australia, located at the bottom of a hill before an intersection

File:Escape Ramp In China Expwy G4511-cropped.jpg|An emergency escape ramp on the G4511 in Heyuan, China

File:TER US 44 Westbound Avon, CT, USA.png|Mechanical-arrestor truck escape ramp (with heated pavement) on US 44 westbound in Avon, Connecticut

File:20141118 Misiryeong Penetrating Road (Emergency Escape Ramp)2.jpg|An emergency escape ramp on Misiryeong Penetrating Road in Gangwon Province, Korea

File:I-176Runway.jpg|I-176 runaway truck ramp in Morgantown, PA

File:Rampa emergenza A18 Sicilia.jpg|Runaway ramp on the A18, Sicily, Italy

File:Escape ramp on the A7 near Amskroud, Morocco.jpg|A 100 meter long gravel escape ramp downhill on the A7 near Amskroud in Morocco

File:Thailand's escape ramp.jpg|An emergency escape ramp on the AH1 in Tak, Thailand

File:Emergency stopping lane in Muğla, Turkey.jpg|Emergency stopping lane in Muğla, Turkey

File:Runaway truck ramp near Silverthorne, Colorado.png|Runaway truck ramp on Interstate 70 near Silverthorne, Colorado

File:Emergency exit on the I-5 road between Ruse and Byala.jpg|Improvised emergency exit for runaway vehicles on the I-5 near Byala, Bulgaria

{{Portal|Transport}}

• Catch points
• Derail
• Engineered materials arrestor system
• Runway safety area (RSA/RESA) for airplanes

{{Reflist}}

{{commons category|Emergency stopping lanes}}

• [https://web.archive.org/web/20120204234159/http://www.webs1.uidaho.edu/niatt_labmanual/Chapters/geometricdesign/professionalpractice/DescendingGrades.htm Design considerations]

• [http://overpass-turbo.eu/s/6VP Query executed on live Openstreetmap data. Move the map to your area of interest and press Run]
• [http://www.kernradio.com/2017/06/22/video-watch-a-semi-slide-into-grapevine-runaway-truck-ramp/ Video: runaway truck on gravel ramp]

{{Road}}

Category:Road safety

Category:Trucks

Category:Road infrastructure

Category:Vehicle braking technologies