Questions tagged [highway-engineering]

Highway engineering covers the design of highways, in particular: layout (vertical and horizontal), surfacing design and drainage

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Will car be able to fit in from this gate from front, as well as from rear?

The gate is 8 ft (96 inches) and the road is 10 ft (120 inches). I am not a engineer nor a professional . Help me calculate stuff, please.
Rihdus Smith's user avatar
2 votes
2 answers
271 views

Why are expansion joints on prestressed concrete box girder bridges sometimes not located directly above the bridge piers?

Here is an example of what I am referring to. This bridge is part of the Tom Moreland Interchange in Atlanta, more commonly known as "Spaghetti Junction". This interchange has several ...
Sagierian's user avatar
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3 answers
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Why are roads sometimes extremely slippery after rain fall?

We've had 5cm of rain in the last week. Yesterday and early this morning it rained. During the morning commute the roads were still wet, but not it was not actively raining. The temperature was $7^{\...
irritable_phd_syndrome's user avatar
1 vote
1 answer
20 views

Can Pavement ME Design be used to other areas besides USA and Canada? [closed]

I live in Asia and would like to use Pavement ME Design for my research. Can the current version of ME Design be used for that? Please give me the answer.Many thanks in advance.
Saowanit Prabnakorn's user avatar
1 vote
1 answer
75 views

Jointed reinforced concrete tie-bar smoothness

We know that in Jointed Reinforced Concrete pavements we use dowels and tie bars. Why are dowel bars Smooth and tie bars are deformed? Dowels are used to transfer about 40% of the load from one slab ...
Alok Subedi's user avatar
2 votes
0 answers
102 views

How fast can the Shinkansen N700 train take a curve?

As a transit advocate, I'm evaluating an urban freeway corridor for high-speed rail. Given the geometry of the existing highway, the track alignment will be a compromise between train speed and right-...
Neal Ehardt's user avatar
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1 answer
84 views

Why have they stopped having curbs on streets? [closed]

Growing up, roads always used to have a clearly separated sidewalk with a height difference. All new streets I see have no such curbs/height differences. Instead, it's just one "blur" of ...
Alvie Savaria's user avatar
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2 answers
843 views

formula for super elevation

I'm practicing some questions for my upcoming exam and I need the formula for super elevation when you've been given the coefficient of lateral friction in the question
user29722's user avatar
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How far have we developed eco-friendly tyres alternatives?

Considering how bad rubber tires is for environment (Microplastic on tyre - NatGeo), Today tires consist of about 19 percent natural rubber and 24 percent synthetic rubber, which is a plastic polymer....
talkingpandas's user avatar
3 votes
2 answers
142 views

Tiled/block pavement used to pave high traffic roadway?

We're normally paving the high-traffic road with concrete or asphalt. While for sidewalk/garden, we use pave block/tiles (either concrete or else) Common reason is because pave block/tiles doesn't ...
gijoe's user avatar
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Any Idea of This China's "Transparent Concrete"?

I am currently make an attempt to make miniaturized version of this China's solar highway on my garage https://www.youtube.com/watch?v=zK8FvzI3yDA Just so i can re-evaluate the performance However, I ...
talkingpandas's user avatar
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2 answers
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Permanent uneven deformation of asphalt car park under portable cabins

Cabins have just been installed on an asphalt car park. The portable cabins weigh 4000 kg with 4 no. 300 mm square spreaders under each foot. The car park is constructed from: 1" thick rolled asphalt ...
egg's user avatar
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What determines when a road should be widened?

I know this depends on a variety of factors including overall traffic volumes, peak traffic volumes, types of vehicles, and type of road, but how exactly do traffic engineers determine how many lanes ...
Sagierian's user avatar
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1 vote
2 answers
639 views

Banking progression in NASCAR tracks

the Bristol Motor Speedway is 0.533 mi long racetrack. The road is banked and circular. The straights are banked to 6–10° and turns to 26–30°. I have made a small diagram for ilustration. Before the ...
Marino's user avatar
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What are these banded earthworks near a freeway overpass for and what are they called?

The satellite view of this overpass (on Google Maps) shows some banded earthworks. When driving by, you can see that each band is an elongated triangular shape (street view): My guess is that these ...
CJ Dennis's user avatar
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Getting the elevation of a specific point of a elevation gridline

In a highway Project, I have to design a road connecting to roads together. The map I have on AutoCAD is a elevation gridlines map and I have x, y and z coordinates but I don't know how to get an ...
Ahmed Madhoun's user avatar
1 vote
2 answers
137 views

NASCAR corners on public roads

Why don't engineers build highways with corners such those on NASCAR speedways?
Marino Klisovich's user avatar
1 vote
3 answers
381 views

What kind of splines should be used when planning roads?

I would like to plan a small road network for an imaginary city, and I am looking for a way to create curved road segments. I am familiar with cubic Bezier curves, but I am not sure if it's the best ...
Iter Ator's user avatar
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2 answers
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How do enginners build highway interchanges ? Are highway interchanges build based on a mathematical theory such as braids and knots theory?

I am trying to find how do enginners build roads especially highway interchanges. Are they relying on any topology theories such as braids and knots theory? Is there any connection or link between ...
Oussama's user avatar
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11 votes
2 answers
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Why was a coil chosen over a straight for this overbridge?

I saw this meme on Facebook showing a coiled railway overbridge and an alternative plan. I replied that straightening that overbridge will force it to start at the other side of the road, and you need ...
Jesvin Jose's user avatar
3 votes
2 answers
255 views

What's sort of "sidewalk" pavement is this?

I was recently walking down a road when a car came my way (I'm an inveterate jaywalker). I moved over to the sidewalk, only to notice it clearly wasn't a sidewalk at all. The pavement looked like this:...
Wasabi's user avatar
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4 votes
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Why are roads straightened when widened?

When widening a road, why does construction seem to inevitably include a "smoothing" out of the curves on the road, essentially making it more straight? I've seen this personally on roads where I ...
Will's user avatar
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3 votes
1 answer
92 views

Street Light Arrangement Method

Hello I am a high school student and I am curious about how street light is arranged along the road. Is there government laws to install street light on the road or is the arangement of the street ...
JSChang's user avatar
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Are there any turborotonde / turboplein designs with more than four exits?

For an at-grade intersection of multi-lane roads, the "Turborotonde" (Dutch language Wikipedia article) or "Turboplein" (Dutch language wegenwiki article) is an alternative to the multi-lane ...
gerrit's user avatar
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For an at-grade intersection of multi-lane roads, what are the (dis)advantages of a "turborotonde" or "turboplein" compared to a classical roundabout?

For an at-grade intersection of multi-lane roads, the "Turborotonde" (Dutch language Wikipedia article) or "Turboplein" (Dutch language wegenwiki article) is an alternative to the multi-lane ...
gerrit's user avatar
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2 votes
0 answers
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How to define the Clothoid Constant in Clothodial Arc ( Spiral Curve)?

Referring to the document here on IfcClothoidalArcSegment2D, we have ClothoidConstant, which is defined as The constant $A$ (not $A^2$), that determines the ...
Graviton's user avatar
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2 answers
116 views

What is the entirety of breadth of road called?

As roadway consists of a width of road on which a vehicle is not restricted by any physical barriers or separation to move laterally source, what is a similar term which encompasses the width of the ...
SF.'s user avatar
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1 vote
0 answers
29 views

Pavement stage construction; reduction of Structual Properties

Which properties of flexible pavement layers are reduced (discounted) in a stage construction design with an overlayed layer? Thickness of stage 1 Layers? Structural Number ? Modulus of Resilience ? ...
user14193's user avatar
1 vote
2 answers
425 views

How to calculate stopping distance with grade?

$$d = \dfrac{V_1^2-V_2^2}{2g\left(\dfrac{a}{g}\pm G\right)}$$ I am wondering if the car travel on the road of a sag curve or crest curve, there is two gradients of the curve. (G1, G2). Which gradient ...
tom's user avatar
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4 votes
7 answers
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Does the speed of Heavy Vehicles make more potholes

Should Heavy Trucks drive more slowly on weak (bitumen) roads to reduce potholes in the road surface? I am discussing with a feasibility engineer what causes more potholes. He says it is simply the '...
Grantly's user avatar
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2 votes
1 answer
367 views

What should a road's traffic volume to justify the number of lanes?

Is there a standard that transportation engineers use for the number of vehicles a road should carry daily for it to be widened to four, six, eight lanes, etc? Curious because I've noticed that some ...
Sagierian's user avatar
  • 171
0 votes
1 answer
179 views

What are the disadvantages of free-flow intersections?

I've recently learned about free-flow intersections. In particular, the DCMI, and the Stack interchanges. What are the disadvantages of using them, compared to the "normal" signaled intersections? do ...
mbrg's user avatar
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3 votes
1 answer
197 views

How can traffic signal controllers handle multiple conflicting preemption requests of equal priority without dropping one?

Let us assume that we are North American traffic engineers, and have the (hypothetical, plausible, yet pathological) intersection configuration depicted (not to scale and lacking lane lines, sorry -- ...
ThreePhaseEel's user avatar
4 votes
1 answer
754 views

How much noise does a road noise barrier block?

I am from The Netherlands, where noise barriers like these are commonly built along motorways: Now I live in England, where such structures are almost non-existent. In The Netherlands, living 200 ...
gerrit's user avatar
  • 321
3 votes
0 answers
72 views

How is a merge left or a merge right chosen?

Recently a certain 2 lane exit ramp changed from merge right to merge left, but the entrance ramp immediately preceding it is merge right. Why was this changed? In a given circumstance, what dictates ...
TrottingGoatParade's user avatar
1 vote
0 answers
49 views

Are there standards or guidance for the placement and location of rest areas on newly constructed or designated U.S. Interstates?

As the highway engineers here may already know, U.S. highway 71 through most of Missouri was recently redesignated as a section of Interstate 49 after the completion of grade separation work at ...
ThreePhaseEel's user avatar
3 votes
3 answers
2k views

Why do North American Roadways Use Yellow Instead of White to Separate Opposing Traffic?

For those of us in the US, we're used to seeing roadways with yellow stripes separating traffic traveling against our direction of travel, and white stripes separating traffic traveling in the same ...
gate_engineer's user avatar
4 votes
2 answers
263 views

How do you call the intersection with barrier and you can always right turn?

In the photo above I can name the first 3 intersection a) Regular intersection b) T intersection c) Skewed intersection I am having a hard time on identifying the fourth intersection, what do you ...
Cary Bondoc's user avatar
-1 votes
1 answer
130 views

What would be the implications of a metal highway design? [closed]

I'm an engineering enthusiast but I don't yet have a formal education in engineering and I'm hoping you guys can tell me about the implications of using a metal road design in terms of durability and ...
J.Todd's user avatar
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8 votes
2 answers
553 views

What is the justification for working on such large stretches of road?

I live and work in the UK, a country known for relentless roadworks. Last week I drove through roadworks on the M1 that lasted for 18 miles, necessitating road users driving at 50 mph. Of course, ...
Phil's user avatar
  • 216
7 votes
3 answers
676 views

How are earthfills not eroded before they are overgrown with grass?

Almost every railroad and vehicle road landfill has its slopes overgrown with grass which is quite good at preventing erosion. However it takes some time (a year or more) for the grass to grow and ...
sharptooth's user avatar
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10 votes
7 answers
5k views

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

If roads were made of removable parts, we'd probably have fiber cable internet everywhere by now I'd say. It'd be so much easier to install e.g. new electricity and water infrastructure and to ...
Yuri Borges's user avatar
5 votes
0 answers
103 views

Effect on pavement by light tracked vehicles with rubber inserts

Is there data available to quantify the effect on pavement by light tracked vehicles with rubber inserts. One example of such a vehicle is the M113 armored personnel carriers shown below.
David's user avatar
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6 votes
1 answer
3k views

Does passenger car traffic actually damage roads?

Pavement Design In roadway pavement design, the (US) controlling design load is usually the Equivalent Single Axle Load (ESAL). This number attempts to quantify how much bending stress a given ...
hazzey's user avatar
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4 votes
1 answer
2k views

How are maximum speed limits determined for banked curves?

I was once told that the speed limits on banked highway curves (specifically off-ramps) were determined by assuming zero friction between the car and the road, such that as long as you stayed on the ...
Ethan48's user avatar
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13 votes
3 answers
18k views

What is a Spiral Curve, and How is it Different from a Normal Curve?

I've heard the term spiral curve used to describe a section of highway that is more aesthetically pleasing to the driver's eye. However, I believe I've driven on enough road to say that I can't ...
gate_engineer's user avatar
3 votes
1 answer
477 views

When are Single Point Urban Interchanges used?

There is a topic discussing the pros and cons of roundabouts. A less common intersection is the Single Point Urban Interchange (SPUI). This is an intersection that seems to be mostly used on ...
hazzey's user avatar
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5 votes
1 answer
252 views

Best traffic control device/system for given situation

I am familiar with the round-a-bout/traffic light pros and cons, however, I've been tasked with deciding on a solution for the given parameters below. Currently, there is a two-way (four lane) road ...
Anthony Burleson's user avatar
10 votes
1 answer
223 views

Has a specific type of alternative intersection been shown to reduce congestion & accidents?

Localities in the US have different road layout and setups. For example the Michigan Left, Jersey Left/Jug Handle, vs a standard 4 way stop with left turns at the intersection. Have any of them come ...
JedF's user avatar
  • 476
35 votes
12 answers
46k views

What are the pros and cons of a traffic circle versus a traffic light intersection?

The debate of traffic circles (also called roundabouts or rotaries) versus traffic light intersections has been in progress for a while. Those in favor of traffic circles say that, among other things, ...
APerson's user avatar
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