THE IMPACT OF ROAD BUMPS ON HIGHWAY MACROSCOPIC TRAFFIC FLOW PROPERTIES

Abstract

Any vertical undulation of the road surface like road bumps or humps tends to affect the traffic flow properties. Bida – Minna road is a highway which serves through traffic movement between Minna; the state capital of Niger State to Bida. Towards the tail end of this road en route to Minna a series of bumps were installed, thus having an impact on traffic flow properties especially during peak hours. This study is focused on assessing the effect of road bumps on highway traffic flow properties. Two distinct sections were taken: Section A; “free section” and Section B; “bump section”. At both sections, volume and speed studies were conducted simultaneously during peak hours. A significant reduction in mean speed of vehicles were observed, from 42.11 km⁄h at free section to 9.21 km⁄h at bump section was observed. Whereas the traffic flow increased from 1,160 Pcu⁄h⁄l to 1,546 Pcu⁄h⁄l with density increasing significantly from 28 Pcu⁄km⁄l at free section to 170 Pcu⁄km⁄l at the bump section and a corresponding rise in operational capacity from 1,270 Pcu⁄h⁄l to 1,776 Pcu⁄h⁄l. The road levels of service changed from the best flow condition ‘A’ at free section to the near worst condition ‘E’ at bump sections. In conclusion, road bumps are best suited for low-speed facilities like parking lots because of its effectiveness in slowing vehicles down to a minimal speed; for this study a 77% loss in mean speed was observed from free section to the bump section, while volume flow rate increased by 4.68% and consequently increasing traffic density by 530% which causes a near congestion condition. Thus, road bumps are not suitable on highways.