capacity and rollover analysis for heavy vehicles.

Details

• Creators:
  Tarko, Andrew P. ; Romero, Mario A.  ; Hall, Thomas ; Matin, Shaikh Ahmad ; Lizarazo, Cristhian G.
• Corporate Creators:
  Purdue University. Joint Transportation Research Program
• Corporate Contributors:
  Indiana Department of Transportation ; United States. Federal Highway Administration
• Subject/TRT Terms:
  Headways Nighttime Crashes Overturning Rollover Crashes Roundabouts Superelevation Trucks
• Publication/ Report Number:
  FHWA/IN/JTRP-2015/26
• DOI:
  http://dx.doi.org/10.5703/1288284316011
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States;Indiana
• Corporate Publisher:
  Purdue University. Joint Transportation Research Program
• Abstract:
  There is a recent trend of building roundabouts on high‐speed roads, often with the considerable presence of heavy vehicles. With
  
  the increased presence of trucks on roundabouts, the issue of overturning has become a concern. Although some geometric, vehicle,
  
  and loading factors have been connected to rollover, the safety performance of roundabouts built on high‐speed roads is not well
  
  understood due to their relative novelty. In addition, other concerns related to geometry, driver behavior, and environmental
  
  considerations may exist at roundabouts. This study examined roundabout circulatory superelevation, aggressive driver behavior,
  
  roundabout readability, and nighttime conditions in the context of heavy vehicle rollover. Moreover, the critical and follow‐up headways
  
  were estimated for trucks and other vehicles at roundabouts located on the low‐ and high–speed roads and during daytime and
  
  nighttime conditions.
  
  This research developed a methodology which may be used to examine truck overturning at roundabouts. A generalized rollover
  
  model suitable for application to heavy vehicles was applied to field‐observed semi‐trailer speeds and paths to estimate their proximity
  
  to rollover at newly‐built Indiana roundabouts. This was done by introducing delta v ‐ the difference between the critical rollover speed
  
  determined from the model and the actual speed.
  
  This report revealed that heavy vehicles increased the critical headway, and in turn reduced the entry capacity of roundabouts.
  
  Drivers of heavy vehicles, on average, accepted a 1.1 sec longer critical headway than drivers of passenger cars. The effects of
  
  nighttime/twilight conditions indicated additional capacity reduction caused by a 0.6 sec longer critical headway compared to daylight
  
  conditions. Likewise, drivers on dual‐lane roundabouts in rural areas accepted a 0.6 sec longer critical headway than drivers on singlelane
  
  roundabouts in urban areas.
  
  It was determined that the gap‐acceptance parameters for a single‐lane roundabout on a low‐speed state road were shorter than
  
  the national values, resulting on average in 30% higher capacity for Indiana conditions. In contrast, the estimated critical headway was
  
  larger for dual‐lane roundabouts on high‐speed state roads, resulting in 15% reduced capacity for Indiana conditions.
  
  The findings of this report are based on low and medium traffic volumes presently observed on high‐speed rural and suburban
  
  roads. Heavy traffic flow may affect driver behavior; therefore, studying such roundabouts in heavier traffic conditions might improve
  
  the results.
  
  
• Format:
  PDF
• Funding:
  SPR-3830
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:b4101f5f6a78530cd0323d99fa302ba8cc87a08c5cffc305602d77305c9825cb3170f412c3b0c609fa565f32c628d8f1b48294512243ff01df0f93d60babc911
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/30938/dot_30938_DS1.pdf
• File Type:
  [PDF - 5.35 MB ]