幼儿园主题亲子活动:翻译 Ideal conditions for uninterrupted

Ideal conditions for uninterrupted flow facilities include the following: lane widths of 12ft ;clearance of 6ft between the edge of the travel lanes and the nearest obstructions or objects at the roadside and in the median ; design speed of 70mph for multilane highways , 60mph for two –lane highways ;only passenger cars in the traffic stream ; level terrain.
Ideal conditions for intersection approaches include the following : lane widths 12ft ;level grade ;no curb parking on the intersection approaches ;only passenger cars in the traffic stream and no local transit buses stopping in the travel lanes ;all vehicles traveling straight through the intersection; intersection located in a non –central business district area ;no pedestrians; at signalized intersection approaches ,green signal available at all times .
In most capacity analyses ,prevailing conditions are not ideal ,and computations of capacity ,service flow rate ,or level of service must include predictive adjustments to reflect this absence of ideal conditions . prevailing conditions are generally conditions that change in the long term.
Roadway conditions
Roadway factors include geometric conditions and design elements .in some cases ,these factors influence the capacity of a road ,whereas in others ,the factors may affect a measure of effectiveness ,such as speed ,while not affecting the capacity or maximum flow rate that can be carried by the facility.
Roadway factors include the following:
1. the type of facility and its development .
2. lane widths
3. shoulder widths and lateral clearances.
4. design speed.
5. horizontal and vertical alignments.
6. availability of queuing space at intersections.