Quoted: Wash boarding, the "ripples" on gravel roads, are caused by the natural frequency of the unsprung mass and the spring rate of the vehicles traveling over these roads.
The frequency or spacing of the wash boarding is related to the speed of the vehicle by the equation of
frequency = (k/m)^1/2
where k is the spring rate and m is the unsprung mass.
Believe it or not, most vehicles have very close ratios of k/m. Because of this, it is most comfortable to travel at speeds that cause this formation because the dampers (shock absorbers) isolate the harshness of the ensuing vibrations.
Not a civil engineering question as they don't do so well in dynamics which is the study most closely associated with this subject...
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Wrong again nancy boy.
The rutting of the road is caused by the fore and aft bouncing of the vehicle. HOWEVER, the best thing to do is avoid the speed that caused the rutting. The excitation freq. being near the natural frequency of the vehicle causes resonance, resulting in the peak amphiltude of displacement.
I guess you forgot that civil engineers RULE THE WASTELAND of earthquake loading.
The reason the curbs split is because the dirt settles under the curb. The curb usually has no steel reinforcement. Concrete is weak in tension. Bottom of the curb is in tension when the dirt settles.
The light timing thing is governed by computer programs and induction coils under the roadway called "loops".
You can cure any highway related problem in the land with enough money and with politicians with enough balls to pend it wisely.
Can't have 800,000 cars driving on a road that was at peak capacity in 1955 and not expect jams.
The science of highway engineering is very well advanced but there's NEVER ENOUGH MONEY.