Passenger car units of vehicles on Singapore expressways

• Main Author: Chong, Llewellyn Zhi Jie.
• Other Authors: Fan Shing Leung, Henry
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Civil engineering::Transportation
• Online Access: http://hdl.handle.net/10356/38888
• Institution: Nanyang Technological University

Passenger Car Units (PCUs) are used in highway capacity analysis and design as a standard measure to convert mixed-traffic flow into equivalent passenger car flow. While there are many methods available for the estimation of PCU values, multiple linear regression was found to be the most suitable for this study. Although a set of PCU values have already been estimated for vehicles travelling on Singapore expressways, these values were developed when the speed limit was 80 km/h. Expressway speed limits have since been raised, likewise for the vehicle speed limits imposed on larger vehicles in Singapore. The purpose of this study was to develop a new set of PCU values under these new speed limits, for level of service E conditions on the expressway. The results of this study found that the new PCU values are smaller than the existing values, with heavy goods vehicles and buses having the largest reduction. The PCU values for motorcycles, light goods vehicles, heavy goods vehicles, and buses are 0.28, 1.17, 1.53, and 1.58 respectively. The PCU values may be smaller due to the effect of increasing the vehicle speed limits for the larger vehicles, and also due to increased aggressive driving behavior of road users.