Stopping Distances for Dry Pavement/Road
These figures are based on the assumption that Because there are differences between various vehicles, the following tables are for guidance only. The biggest factor in stopping distances is the speed at which a driver reacts to seeing the hazard in question. Under ordinary driving conditions, very few drivers indeed can get onto the brakes within half a second, and two-thirds of a second to a full second is more typical.2
Most frighteningly, Australian research has shown that the very people we expect to have the fastest reactions -- young drivers -- are particularly prone to effectively 'freeze up' with fear, at the sight of an unexpected hazard ahead, and their reaction time can therefore exceed two seconds.
Lastly, don't forget that when you read the 60-0mph figures in literature for new cars, the automaker is giving you only the braking distance, not the overall stopping distance.
QUESTION 3B:
(80+320) = 400 feet
Stopping distance = thinking distance + braking distance
QUESTION 4 - Several key changes to design can be considered as a means to improve pedestrian impact performance:
- Bumper foam needs to be 20-40mm thicker than on current vehicles and may need to be bigger in the vertical direction.
- “A low level foam-covered beam is needed to reduce rotation of the knee joint. This could be disguised under a spoiler-style skin..”
- Lights should be kept below the upper leg crush zone or designed to deform in a controlled way.
- Under bonnet clearance should be at least 75mm, with special consideration paid to major features such as shock absorber mounts. Some suggestions have been made that double-wishbone suspension may be an alternative - this depends on the packaging in this area.
QUESTION 5:
- Cargill’s SafeLane® surface overlay is a patented combination of epoxy and aggregate that acts like a rigid sponge, storing anti-icing chemical applied before storms, then automatically releasing it as snow and ice conditions develop. It also provides superior friction, giving drivers better traction year-round, while sealing pavements to help prevent their degradation.
- Road surface marking is any kind of device or material that is used on a road surface in order to convey official information.
Road surface markings are used on paved roadways to provide guidance and information to drivers and pedestrians. Uniformity of the markings is an important factor in minimizing confusion and uncertainty about their meaning. Countries and areas categorize road surface markings in different ways. -
-theoretical approach to bulk water drainage properties at the tire/road surface interface for a freely rotating tire is presented. The results show that it is possible to optimize the road surface macrotexture conditions (aggregate size, aggregate spacing, and absolute texture depth) to give the minimum time for removal of bulk water from the interface yet give the maximum possible actual area of contact between the tire and road surface to obtain the maximum possible friction levels
CRASH BARRIERS -
A crash barrier is a barrier on a road designed to prevent vehicles from leaving the roadway to improve road safety. Common sites for crash barriers are:
* median separators on multi-lane highways
* bridge supports
* mountain roads
The design of the road barrier is generally such that a vehicle hitting the barrier is steered back onto the road. This may be achieved by designing the supports so that they break off on impact, allowing the barrier to deform and push the vehicle back on track. In some cases cost cutting has led to a failure of this mechanism, with so-called "duck-nesting" (after the shallow nature of a duck nest) of barrier support bases. When this happens the supports tilt over at the base instead of breaking off, allowing the barrier to collapse and the vehicle to go over the barrier. Motorcycles are very vulnerable to crash barriers.
Large vehicles with a high centre of gravity, such as Sport utility vehicles, are also vulnerable to going over barriers on impact.
