Collector Streets
Collector streets connect the residential streets with arterial routes. They may have significant truck and bus traffic and their closure for paving could create substantial commuter delays.
Figure 1: Collector Streets
Figure 2: Collector Streets
Assumed Traffic
Low to intermediate speed, moderate traffic volume and some heavy loadings. Truck traffic can often include substantial amounts of delivery vehicles, school buses and, sometimes, public transit buses. You can use the following as a template for the Equivalent Standard Axle Loads (ESALs) used in the structural design of asphalt pavements.
| Vehicle Type | Vehicles per day |
Vehicles per year |
ESALs per year |
|---|---|---|---|
| Cars and Light Trucks | 3,500 | 1,300,000 | 900 |
| Medium Trucks and Buses | 100 | 36,500 | 9,000 |
| Heavy Trucks and Buses | 20 | 7,000 | 10,000 |
| Totals | 3,620 | 1,343,500 | 19,900 |
Design Considerations
Collector street traffic loading can vary widely. High traffic streets (specifically those with substantially higher heavy truck and bus traffic levels than those listed above) should be designed using an approved structural design procedure. The state-of-the-art tool for pavement design is PAVEXpress ( www.pavexpress.com & www.paveinstruct.com). This free, on-line tool automates the AASHTO 1993/ 98 Guide for Design of Pavement Structures and makes running alternate pavement design scenarios for comparison extremely simple.
Construction Considerations
Consideration should be given to paving in two separate lifts to allow street use with only minimal delays during construction. Any localized failures in the first lift can be repaired before final lift placement. A lower cost asphalt treated base (ATB) base list is ideal for this staged paving strategy and can save time and effort in several ways (clean worksite, clean storage of materials, protection of the grade from weather during construction etc.).
Recommended References
- American Association of State Highway and Transportation Officials (AASHTO). (1993). AASHTO Guide for Design of Pavement Structures. American Association of State Highway and Transportation Officials. Washington, D.C. (AASHTO)
- The Asphalt Institute. (1999). Thickness Design – Asphalt, Manual Series No. 1. The Asphalt Institute. Lexington, KY. (Asphalt Institute)
- National Asphalt Pavement Association (NAPA). (2001). HMA Pavement Mix Type Selection Guide, Information Series 128. National Asphalt Pavement Association. Landham, MD. (NAPA)
