Managing speed behaviour by defining speed limit and traffic calming strategies in CBD area :: Case study city main CBD area, Brebes Regency Indonesia
PRISMAN, Mochammad Reza, Prof. Dr-Ing. Ir. Ahmad Munawar, M.Sc
2010 | Tesis | S2 Magister Sistem Teknik dan Transportasiunavailable
There are various traffic characteristics in CBD area in Brebes Regency, shown by the mix between distance traffic, which usually with high speed, and local traffic. This condition made the local traffic, which usually light vehicle, motorcycle and pecidab (un-motorized), are potentially dangerous related to the traffic accident. The local traffic authority has regulated the speed limitation on CBD area, by stating 40 km/h for the inner CBD area and 50 km/h for the outer. However, the traffic accident still occurs, and according to the accident data 2007-2008, the lowest zero accident probability is reaching 0.189 (Gadjah Mada road, west-east direction), while the highest zero accident probability is only 0.453 (Sudirman road, section 2), which means that there are high probability for traffic accident. From the speed limit violation identification shows that the highest violation occurs in Sudirman road section 3 on 3rd peak hours (16.00- 17.00), while 91.6% vehicle breaking the speed limit. And the lowest violation (2.3%) is occurred in Gajah Mada road, east-west direction on 1st peak hours (07.00-08.00). Reducing the traffic speed is the chosen method to increase the safety and reduce speeding problems in the CBD area. These traffic calming strategies e.g. proposing speed table, rumble strips and raised crosswalk installation, integrated by road coloring/texturing such as “school safety zone†and other colored pavement strategies, will be employed to reduce the traffic speed then also to increase the safety level on the road. The indicators of changes are the vehicle speed (85th percentile), road performance level (the changes should not exceed the E level - <0.85), accident probability (increased zero accident probability), and body injury rate (decreased the injury rate for pedestrian accident). The result shows that using the proposed strategies, all requirements are fulfilled to meet the demands of increasing road safety level in CBD area. In example, Diponegoro road west-east direction, by installing rumble strips and raised crosswalks with certain measurement, can reduce the approaching speed from 51.21 km/h to 38.33 km/h, increases the zero accident probability from 0.233 to 0.54, decreases body injury rate (if there are pedestrian accidents) from 80- 85% to 25-30%. Even though the level of service decreases from 0.46 (C) to 0.76 (D), but there is no significant problem, because the level of service is still acceptable.
Kata Kunci : Trafic calming,Trafic accident,Speed management and engineering,Space mean speed