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A hazard prevention symbol is an essential safety communication tool in helping to indicate the various hazards present. The hazard prevention symbol warns against caution, providing needed safety information and instructions. This study aims to determine the understanding of symbols of danger and driving behavior on toll roads, especially the Tangerang-Merak toll road. The sampling method was carried out using a random sampling sample. Safety behavior will be assessed using the Driver Behavior Questionnaire (DBQ). The results obtained by car drivers on toll roads, on average, understand the symbol of hazard communication in horizontal alignment conditions, vertical alignment, and dangerous road warnings. However, many drivers need help understanding the communication hazard symbol on the lane separator construction. Based on the Driver Behavior Questionnaire, sequentially, the deviant behavior of car drivers on the Tangerang-Merak toll road, namely violations, lapses, and errors.

The Jakarta Outer Ring Road (JORR) is a toll road system that circles the outskirts of Jakarta, where the purpose of this road is to reduce congestion on the street network of the city centre of Jakarta. However, the high composition of trucks in JORR resulted in congestion, and moreover it is suspected that the steep gradient of this road has contributed to this situation. This study aims to investigate the impact of road gradient on the trucks and the overall traffic performance from macroscopic view point. This study is the complement to a similar study that has been done in JORR previously, to confirm the result. The previous study was based on the Vissim simulation, while this paper will be entirely focused on an empirical study. Using the data obtained from 24-hour traffic recording on selected JORR sections that represent various gradients, traffic flow models are generated, and the effect of gradient could be assessed. The speed difference between trucks and non-trucks shows 56.2%~127% gap as the result of different gradient occurred. The overall free flow speed (uf) difference of different gradient is up to 27.3%. This result will benefit to the transport authority to justify the policy concerning the existence of trucks in the traffic flow, particularly in the condition at which trucks are regarded as a culprit of traffic congestion.