7 votes
Accepted

What would be the implications of a metal highway design?

Asphalt, which is essentially crushed aggregate bound with bitumen has a lot of advantages for road building. It is porous and so can drain by allowing water to pass through it as well as running ...
Chris Johns's user avatar
  • 15.2k
5 votes

Speed breaker design

Shallow, wide speed bumps are easy fore slow traffic while offering more or less the same impact as narrow, high speed bumps. Because the impulse force remains the same for fast speed. They are having ...
kamran's user avatar
  • 22.4k
5 votes

Vehicle load factor discrepancies

I think you are possibly concentrating on the wrong thing. From your state.pa.us link: The VLF of a passenger car (.0004) is so small that cumulative pavement impact is essentially moot So, ...
AndyT's user avatar
  • 3,153
5 votes

What kind of splines should be used when planning roads?

Roads are usually designed using catenary curves. https://sketchup.engineeringtoolbox.com/catenery-curve-c_169.html Road curves are designed around vehicle velocities and they are not uniform. As ...
Rhodie's user avatar
  • 964
5 votes

What kind of splines should be used when planning roads?

Circular arcs are not used except in special situations, because the sudden change in curvature from a straight road to a circular arc would mean drivers had to quickly turn the steering wheel to the ...
alephzero's user avatar
  • 12.5k
4 votes
Accepted

NASCAR corners on public roads

Public roads must be safe to handle slow, heavy traffic and be safe to pull over a stalled car under a snow storm. They should be flat enough to make it easy for emergency services such as ambulances,...
kamran's user avatar
  • 22.4k
4 votes

Why do the sidewalks on USA roads use big, massive stone plates instead of asphalt?

Slipform paving isn't that big a deal, some basic ground preparation, then follow the line. The contraction joints are added to the wet concrete either by the machine or by workers with hand tools. As ...
Phil Sweet's user avatar
  • 4,755
3 votes

Why have they stopped having curbs on streets?

On the following roads, a curb is not desirable - highway without pedestrian traffic, rural highway (ease of pulling to the shoulder and not to restrict water flow to ditches), City streets designated ...
r13's user avatar
  • 8,194
3 votes

Speed breaker design

Several companies have developed speed bumps / speed breakers that "disappear" when driven over below a set speed. My favourite designs are those that use non-Newtonian fluids. See this ...
Transistor's user avatar
  • 10.7k
3 votes

Banking progression in NASCAR tracks

In highway design, this is called a superelevation and spiral transition: https://en.wikipedia.org/wiki/Track_transition_curve The length of the spiral is based upon the design speed. For USA highway ...
DavidJ's user avatar
  • 154
3 votes

Why do we pave roads instead of making them from removable parts?

Other answers have well described a road is a lot more than just the surface layer and the vast majority of the cost is the planning and logistics involved rather than the actual materials. Current ...
Chris Johns's user avatar
  • 15.2k
3 votes

How do enginners build highway interchanges ? Are highway interchanges build based on a mathematical theory such as braids and knots theory?

It's much closer to graph theory. First, traffic projections: basing on known and projected urban data - habitation, production, recreation, trade zones, transit, etc, the general transition patterns ...
SF.'s user avatar
  • 6,135
2 votes

Does rain cause Tarmac / asphalt pot holes? If so, how?

old tarmac has cracks in it which can admit water under the material, softening the earth underneath. when a vehicle rolls over the cracked material, it yields because the softened earth fails to ...
niels nielsen's user avatar
2 votes

NASCAR corners on public roads

The banking on speedways are designed for speeds in excess of one hundred miles per hour (160 kmh) and cannot maintain a vehicle position at speeds below a certain level. For ordinary traffic speeds, ...
fred_dot_u's user avatar
  • 7,080
2 votes

Tiled/block pavement used to pave high traffic roadway?

Engineering decisions are fundamentally about problem solving. Thus, when asking, "Why not do [x] instead of [status quo]?" an answering question is: "What problem does [x] solve or ...
CableStay's user avatar
  • 2,760
2 votes

Why are roads sometimes extremely slippery after rain fall?

Usually roads become slippery after a first rainfall of the season because of all the dust and oil particles that have not been washed away and they are mixed with the moisture. Basically they create ...
NMech's user avatar
  • 24.3k
2 votes

Speed breaker design

A common approach in residential areas where I live is to occasionally move a lane a car width towards the edge of the road every few thousand feet then back, with a small median and curb between the ...
jko's user avatar
  • 2,347
2 votes

How do "Your Speed" Signs work, and how do vehicles know when it's the sign's turn to display their speed?

These are almost certainly Doppler systems (addressing some comments). The transmitted beam, be it radar or lidar, is focussed and aimed to cover the approaching lane at a decent distance. If it's ...
Carl Witthoft's user avatar
1 vote

Why are roads sometimes extremely slippery after rain fall?

Hydroplaning - By definition, hydroplaning is when a vehicle starts sliding uncontrollably due to the tires encountering more water than the treads can displace. When driving at high speeds over wet ...
r13's user avatar
  • 8,194
1 vote

Why are roads sometimes extremely slippery after rain fall?

As you mentioned bitumen, tire rubber particles, fine dust, and oil can cause a roud to be slippery after a dry spell. But in your case it's not that. it could be a caravan of old trucks crossing the ...
kamran's user avatar
  • 22.4k
1 vote

Speed breaker design

What you are talking about is called traffic easing or calming. The best solutions include the design of the road and everything around it. We build big wide roads and are somehow surprised that ...
Tiger Guy's user avatar
  • 6,881
1 vote

Tiled/block pavement used to pave high traffic roadway?

The reason tiles or flagstone or any other finishing is not used for heavy trrafic areas is lack of strength and toughness. Even in the decks you have attached photos these tiles/ stones will crack ...
kamran's user avatar
  • 22.4k
1 vote

Are storm drains put after road has been finished and asphalted?

Most civil engineering jobs in the countries I have lived in are planned in a logical order, basically deep stuff - like provision for drains, then the foundations necessary and further pipes, drains ...
Solar Mike's user avatar
  • 15.8k
1 vote

What kind of splines should be used when planning roads?

Clothoid? I recall hearing that some roadway curves are designed using the Clothoid Spiral AKA the Spiral of Cornu AKA https://en.wikipedia.org/wiki/Euler_spiral in which the (radius of) curvature ...
Catalyst's user avatar
  • 161
1 vote

Street Light Arrangement Method

Street lights are installed in order to provide a minimum lighting level along the roadway. Some municipalities or states or countries may have minimum lighting standards, but these often vary ...
MacsAre1's user avatar
  • 171

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