Truck Safety in North Carolina and Human Factors (updated 04-17-00)

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CMV Risk Management Efforts (PDF Format, 459k) HSRC analysis efforts in support of FMCSA risk management requirements are described. The material also describes efforts to promote the use of Geographic Information Systems (GIS) technologies, efforts to document the 'capacity' of CMV enforcement resources, and the type of functional analyses being carried out to quantify the 'effectiveness' of alternative enforcement strategies.

Geographic Information Systems (GIS) plots of '98 and '99 fatal truck crashes in North Carolina (PDF Format, 133k) The two charts show different GIS views of fatal truck-involved crashes in North Carolina for 1998 and 1999. The first uses a 'clustering' tool to display crashes which occurred within a given radius of population areas of greater than 40,000. The bar chart shows what percentage of total fatal crashes are captured depending upon the radius of the cluster (e.g., approximately 55 percent of all fatal truck-involved crashes occurred within 20 miles of urban areas with populations greater than 40,000.) In the chart to the right, 'municipalities' rather than large urban population areas are used as a basis for defining the clusters. While capturing a higher percentage of total crashes, it is not clear how informative the plot is in terms of differentiating the geographical/spatial magnitude of the truck crash problem. In the second chart, fatal crash 'densities' are represented graphically in terms of a shading algorithm (light shades indicate lower densitites; darker shades indicate higher densities). The density display in this particular case is more informative than the population-centered clustering display, in that it allows one to view the relative magnitude of the problem and to do so independently of any arbitrary reference to population or juridicational boundaries. (Note: GIS support of HSRC truck safety analysis efforts is being provided by the North Carolina Center for Geographic Information and Analysis)

Long Term (1991-1999) View of Heavy Truck Crashes in North Carolina. (PDF Format, 14k) Data are presented in the accompanying chart on a quarter-by-quarter basis. Red points are fatal-only crashes; blue bars are ALL heavy truck involved crashes (including fatals). Trendlines show crashes beginning to level off sometime around 1995-1996, while fatal crashes continued to increase. This does not refute the success observed by DMV Enforcement in reducing fatals in calendar year 1999, or in the 21-county area in FY99. Middle image shows the percent of heavy truck involved crashes during this period which involved injuries (including fatalities). Trend is relatively unchanged over this period. . . i.e., about 60 percent of heavy truck-involved crashes consistently involved some level of injury. The bottom portion of chart shows the percent of injury crashes involving one or more fatalities. The trendline in the bottom figure shows a slight decrease in the likelihood of crashes involving a fatality over the period from about 1992-1996, then increasing from 1996 onward. The polynomial equation defining the trendline, while capturing major shifts during this overall period, does not accurately reflect the observed reduction in fatals in 1999 (refer to last four data, especially their relationship to the previous year (1998).

Angle Crashes on Interstate and Non-Interstate Roadways. (PDF Format, 27k) Data are presented for fatal truck-involved 'angle' crashes on North Carolina interstate and non-interstate roadways. The focus is on whether or not a violation was cited in the crash and the type of violation. In non-interstate crashes, the pattern of violations suggests problems with traffic control at access points (i.e., failure to stop, yield, etc.). On interstates, 58% of citations issued in fatal truck-involved crashes are for speed related violations. These particular data do not indicate whether it was the driver of the truck or other vehicle who was cited.

North Carolina's I-95 Corridor: Facts concerning truck safety in the nine counties bordering I-95. (PDF Format, 1,875k) Images are provided for each county showing location of fatal truck-involved crashes during 1998 and 1999 (limited data). Images are from GIS Crash Referencing System being developed for commercial vehicle application by the UNC Highway Safety Research Center and the North Carolina Center for Geographic Information and Analysis (http://cgia.cgia.state.nc.us:80/cgia/).

Why do motorists pull out in front of large trucks? (PDF Format 22k) Examines plausible reasons based upon driver experience, human perceptual limitations, and a lack of appreciation for the increased stopping distances required by large trucks. Includes data comparing stopping distances of mid-size passenger cars and 80,000 lb loaded tractor-trailers traveling on dry, level road surfaces.

Reductions in Fatal Truck-Involved Crashes in 21-County Area: (PDF Format, 137k) A brief overview of the success of NCDMV commercial motor vehicle (CMV) enforcement efforts in reducing fatal truck-involved crashes during fiscal year 1999 (Oct 1998 thru Sep 1999).

Evaluation of NCDMV's FY99 Commercial Vehicle Safety Plan (CVSP): (PDF Format, 903k) Provides a detailed evaluation of the extent to which FY99 CVSP ‘goals' were achieved, with an emphasis on those activities related to the reduction of fatal truck-involved crashes in the 21-county ‘target' enforcement area.

Expanded 31-County Enforcement Area: (PDF Format, 134k) Major enforcement areas based on CMV crash data are highlighted in the top portion of the chart against a background which shows the eight DMV enforcement districts in the state. The bottom portion of the chart highlights (a) those counties of the original '21' still on a revised list of the top 21 counties in terms of CMV crashes; (b) 'new' counties appearing on the top 21 list in FY99; (c) those counties on the original list of '21' not appearing on the list in FY99, but needing to be 'sustained,' and (d) the combined set of original, sustainment, and new counties.

Analysis of Fatal Large Truck Involved Crashes in North Carolina from 1993-1997  (PDF Format, 434K) Focuses on the involvement of large trucks in fatal highway crashes using data from the Fatal Accident Reporting System (FARS) as well as state crash data complied by the North Carolina Division of Motor Vehicles. The study was supported by the NC Governor's Highway Safety Program (GHSP) as part of an effort to remove North Carolina from NHTSA's "Top Ten" list of states in terms of fatal truck crashes.

Truck-Involved Crashes and County Population Size (1998)  (PDF Format, 110K) Relates the number of fatal and non-fatal truck involved crashes in North Carolina to the size of the population in the county in which the crash occurred. Statewide data are provided as well as data for a 21 county area specially targeted for increased CMV traffic enforcement activity.

North Carolina FY2000 Commercial Vehicle Safety Plan (CVSP)  (PDF Format 180K) Provides the 'Evaluation' section of the FY2000 CVSP submitted by the NC Department of Motor Vehicles Enforcement Unit to the federal Office of Motor Carriers. The report provides an assessment of DMV Enforcement performance as measured by specific performance goals set forth in the CVSP.

NC Commercial Vehicle Safety Bill (House Bill 303, Ratified 7-21-99) Provides a direct link to the 'Truck Safety' bill recently enacted by the state legislature as part of North Carolina's effort to improve truck safety in the state.

Top 21 North Carolina Counties in FY98 and FY99 in Terms of Overall Truck-Involved Crashes and Fatal, Truck-Involved Crashes - Prior to FY98, the Enforcement Section of the NC DMV, in conjuction with the traffic engineering branch of the NCDOT, identified the 21 North Carolina counties with the highest number of CMV-involved crashes. The list of 21 ‘high crash' counties has been used as the basis for ‘targeting' increased CMV enforcement efforts. The first table provides a review of CMV-involved crashes (overall) and CMV-involved fatal crashes on a county-by-county basis for all 100 counties in the state (county by county data PDF Format). Those counties in the original list are highlighted. The second table provides a ranking of the top 21 counties for FY98 and FY99 in terms of overall CMV-involved crashes and in terms of CMV-involved ‘fatal' crashes (list of top 21 counties in FY98 and FY99 PDF Format). The third chart documents the success of the increased DMV enforcement effort within and outside the 21-county area. (chart showing DMV effectiveness in 21 county area PDF Format) The data show that while crashes came down by an average of 4-5 percent in both the targeted and non-targeted counties, the number of ‘fatal' CMV-involved crashes was reduced by approximately 17 percent in the ‘target' area while fatal CMV-involved crashes outside the 21-county area actually increased. The fact that only 8 of the original 21 counties appears on the list of the top 21 fatal crash counties in FY99 is a reflection of the success of the increased enforcement efforts in those counties. On the other hand, the appearance of 12 counties not on the original NCDOT/DMV list suggests the need to re-evaluate those counties contained in the ‘target' area, and perhaps more importantly, to evaluate the feasibility of extending the concept of ‘increased CMV enforcement' statewide.

CMV Crash Risk: Relationship to Carrier Size, Out of Service Violations, and Average Number of Moving Violations Per Driver - (PDF Format) Carrier specific data for calendar year 1998 truck-involved crashes in North Carolina were downloaded from the A&I Online website (http://ai.volpe.dot.gov/mcspa.asp) and used as a basis for the analyses reported in these slides. These data show that carrier crash risk in calendar year 1998 (in terms of crashes per power unit) was significantly higher for the smaller carrier. Eight of the top 10 carriers in terms of crash risk were North Carolina-based companies. While experiencing a higher crash risk, the smaller carrier (1-50 power units) contributed only about 10 percent to the total number of fatal truck-involved crashes in the state. The out-of-service (OOS) and moving violation data revealed that driver and vehicle out-of-service rates varied little across carrier size. The only variable showing a clear relationship to carrier crash risk was the average number of moving violations per driver. The data also showed that driver moving violations increased as size of the carrier decreased. Thus while larger carriers had a safer operating record (in terms of crashes per power unit), their exposure (in terms of overall number of power units being operated) contributed to the majority of truck-involved crashes on North Carolina roads.


Comments, suggestions, or for further information, contact: The University of North Carolina Highway Safety Research Center CB# 3430 Chapel Hill, NC 27599 919-962-2202 or (in NC) 800-672-4527 or Contact: Dr. Ronald Hughes