Safety evaluation of urban roundabouts in India: a safety performance function-based approach
There is a lack of comprehensive research in roundabout safety under non-lane-based traffic conditions, mainly due to the absence of relevant crash data and effective tools for safety evaluation. Safety Performance Function (SPF) is a suitable tool for providing valuable information related to fact...
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| Format: | Article |
| Language: | English |
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Technology and Society, Faculty of Engineering, LTH, Lund University
2022-10-01
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| Series: | Traffic Safety Research |
| Subjects: | |
| Online Access: | https://tsr.international/TSR/article/view/24335 |
| _version_ | 1811250652721971200 |
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| author | V S Vinayaraj Vedagiri Perumal |
| author_facet | V S Vinayaraj Vedagiri Perumal |
| author_sort | V S Vinayaraj |
| collection | DOAJ |
| description |
There is a lack of comprehensive research in roundabout safety under non-lane-based traffic conditions, mainly due to the absence of relevant crash data and effective tools for safety evaluation. Safety Performance Function (SPF) is a suitable tool for providing valuable information related to factors which can potentially contribute to the likelihood of increasing traffic crashes. Currently, very limited studies are available to explain the usefulness of SPF in the vicinity of roundabouts, especially at non-lane-based traffic conditions. This study aims to develop an SPF model for assessing the safety evaluation at roundabouts as a whole (intersection level) and the approach level. Data corresponding to crashes in nineteen roundabouts with different geometric and traffic characteristics was used for model formulation. Crash data for five years (2015–2019) was obtained from the State Crime Records Bureau. An SPF model was developed using a negative binomial model with a log-link function based on the number of crashes, traffic characteristics, and geometry characteristics of the roundabouts. The proportion of powered two-wheelers, percentage of heavy vehicles, entry-angle, and weaving-length were all significantly related with higher crash occurrences at roundabouts, according to the findings. In contrast, the number of circulatory lanes, inscribed circle diameter, and presence of road lane marking were negatively associated with the increased crash occurrences at the roundabout vicinity. In addition to this, the overall crash rate significantly varies across roundabout sections due to the asymmetric effects of geometric and traffic characteristics. The developed SPF would best explain the relationship between geometric and traffic characteristics and the crash occurrence rate in non-lane traffic conditions. The findings of this study support the need to relook at design parameters for better movement at the roundabouts, thereby improving the existing facilities to enhance road users' safety, especially in developing countries. The proposed SPF tool would help engineers examine the safety of roundabouts in terms of design adequacy, quantifying the risk factors, and future crash predictions.
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| first_indexed | 2024-04-12T16:07:52Z |
| format | Article |
| id | doaj.art-416b40f85af44f6798603afcb682743d |
| institution | Directory Open Access Journal |
| issn | 2004-3082 |
| language | English |
| last_indexed | 2024-04-12T16:07:52Z |
| publishDate | 2022-10-01 |
| publisher | Technology and Society, Faculty of Engineering, LTH, Lund University |
| record_format | Article |
| series | Traffic Safety Research |
| spelling | doaj.art-416b40f85af44f6798603afcb682743d2022-12-22T03:25:59ZengTechnology and Society, Faculty of Engineering, LTH, Lund UniversityTraffic Safety Research2004-30822022-10-01310.55329/bylj4120Safety evaluation of urban roundabouts in India: a safety performance function-based approachV S Vinayaraj0Vedagiri Perumal1Indian Institute of Technology Bombay, IndiaIndian Institute of Technology Bombay, India There is a lack of comprehensive research in roundabout safety under non-lane-based traffic conditions, mainly due to the absence of relevant crash data and effective tools for safety evaluation. Safety Performance Function (SPF) is a suitable tool for providing valuable information related to factors which can potentially contribute to the likelihood of increasing traffic crashes. Currently, very limited studies are available to explain the usefulness of SPF in the vicinity of roundabouts, especially at non-lane-based traffic conditions. This study aims to develop an SPF model for assessing the safety evaluation at roundabouts as a whole (intersection level) and the approach level. Data corresponding to crashes in nineteen roundabouts with different geometric and traffic characteristics was used for model formulation. Crash data for five years (2015–2019) was obtained from the State Crime Records Bureau. An SPF model was developed using a negative binomial model with a log-link function based on the number of crashes, traffic characteristics, and geometry characteristics of the roundabouts. The proportion of powered two-wheelers, percentage of heavy vehicles, entry-angle, and weaving-length were all significantly related with higher crash occurrences at roundabouts, according to the findings. In contrast, the number of circulatory lanes, inscribed circle diameter, and presence of road lane marking were negatively associated with the increased crash occurrences at the roundabout vicinity. In addition to this, the overall crash rate significantly varies across roundabout sections due to the asymmetric effects of geometric and traffic characteristics. The developed SPF would best explain the relationship between geometric and traffic characteristics and the crash occurrence rate in non-lane traffic conditions. The findings of this study support the need to relook at design parameters for better movement at the roundabouts, thereby improving the existing facilities to enhance road users' safety, especially in developing countries. The proposed SPF tool would help engineers examine the safety of roundabouts in terms of design adequacy, quantifying the risk factors, and future crash predictions. https://tsr.international/TSR/article/view/24335negative binomialroundaboutssafety performance functionweaving length |
| spellingShingle | V S Vinayaraj Vedagiri Perumal Safety evaluation of urban roundabouts in India: a safety performance function-based approach Traffic Safety Research negative binomial roundabouts safety performance function weaving length |
| title | Safety evaluation of urban roundabouts in India: a safety performance function-based approach |
| title_full | Safety evaluation of urban roundabouts in India: a safety performance function-based approach |
| title_fullStr | Safety evaluation of urban roundabouts in India: a safety performance function-based approach |
| title_full_unstemmed | Safety evaluation of urban roundabouts in India: a safety performance function-based approach |
| title_short | Safety evaluation of urban roundabouts in India: a safety performance function-based approach |
| title_sort | safety evaluation of urban roundabouts in india a safety performance function based approach |
| topic | negative binomial roundabouts safety performance function weaving length |
| url | https://tsr.international/TSR/article/view/24335 |
| work_keys_str_mv | AT vsvinayaraj safetyevaluationofurbanroundaboutsinindiaasafetyperformancefunctionbasedapproach AT vedagiriperumal safetyevaluationofurbanroundaboutsinindiaasafetyperformancefunctionbasedapproach |