Traffic impact assessment of a large-scale residential development on urban collector roads

Abstract

Background: Rapid residential expansion at metropolitan fringes can increase traffic demand on collector roads, create access conflicts, and reduce operational reliability at median openings. This study assessed the traffic implications of the planned Sunville Residence development on Tun Abdul Razak Road in Paccinongang, Gowa Regency, Indonesia. Methods: The analysis synthesized a 2025 traffic impact study covering road geometry, road capacity, weekday and weekend traffic volumes, degree of saturation, level of service, U-turn maneuver times and queue ratios, trip production and attraction, directional distribution, mode share, network loading, parking demand, public transport access, pedestrian facilities, and forecasts to 2032. Capacity calculations followed the Indonesian Road Capacity Guidelines, while the development scenario added approximately 160 passenger-car units per hour and applied an annual traffic growth rate of 2.98%. Findings: The divided four-lane collector had a reported capacity of 6,314.9 passenger-car units per hour. Existing weekday peak degree of saturation was 0.52 on TAR and 0.55 on TAR II. With development, these values increased to 0.54 and 0.57. Medium vehicles produced the highest U-turn queue ratios, reaching 0.58 at U-turn I and 0.31 at U-turn II. Weekday peak development traffic reached 164 passenger-car units per hour, and 77.3% of generated movements were assigned toward Makassar. Motorcycles represented 84.1% of the observed daily vehicle count. By 2032, weekday peak saturation was projected to reach 0.65 on TAR and 0.69 on TAR II, with the reported level of service declining to D on the most critical weekday periods. Commercial and shophouse uses required 320 parking spaces, including 214 motorcycle, 101 car, and 5 truck spaces. Conclusion: The road network can accommodate initial development traffic, but the limited operational reserve at TAR II, concentrated Makassar-oriented trips, U-turn queuing, and motorcycle-dominated flow require staged access management, safe pedestrian-transit connections, parking control, and annual performance monitoring. Novelty/Originality of this article: This study integrates link performance, median-opening operations, travel-demand components, multimodal access, parking, safety, and pavement-risk considerations within one development-level assessment for a motorcycle-dominated peri-urban corridor.