freeway and expressway operations

8/11/2019 Freeway and Expressway Operations

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Freeway and Expressway

Operations


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Freeways are designed for high speed, free flowing, low

accident facilities and operate without hindrances from

traffic control. This type of roadway operates well because of

their isolation from the surroundings with widely spaced

access and barred pedestrians. However, because of itsisolation, it is difficult to call for and render assistance in case

of accidents or vehicular breakdown.


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Recommended Relief to Alleviate

Congestions


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Ramp Control

1. The most common cause of traffic breakdown is adding more vehicles

on the ramp. Thus, ramp control is necessary to prevent the flow

disruption.


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2. Entry of vehicles on the ramp should be restricted or stopped when

breakdown on the flow of the freeways is noticed.


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Delaying Traffic

3. It is better to delay the few motorists who wish to enter the ramp than

those motorists travel on the freeway.


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Closing a highway

4. A simple solution to congestion on the ramp is to close the rampcompletely before the flow on the freeway reaches critical level. That is, if the

rate of flow reaches a pre-determined level or by closing the ramp during peak

periods.


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Service road or Arterial road

5. The use of service roads or arterial streets parallel to freeways during

peak hours would gain road capacity.


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Motorist Problems on Freeways and

Expressways

1. The motorists are completely isolated from thesurrounding community. The ramps that they could exitare far spaced, and sometimes several kilometers apart inrural areas, and toll facilities are separated in kilometersor more in urban districts.

2. Walking on freeway shoulder is very dangerous.

3. It is almost impossible to walk on elevated structure thathave neither shoulders nor walkers.

4. Motorists would not like to leave their vehicles for fear of

robbery an attack.5. Modern vehicles are now complex and diverse in design

that repairs by the driver or passing motorist is difficult.


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Freeway Shoulders


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SOLUTIONS:


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1. Highway patrol should provide systematic surveillance


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2. Emergency radio or telephone installed at roadside.


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Emergency Vehicles and Crews

3. Emergency vehicles and crews should standby on call to remove

obstructing vehicles as quickly as possible.


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Patrol Cars Along The Freeways

4. The agencies concerned should detail patrol cars along the freeways

for immediate assistance to motorists.


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STREET LIGHTINGS


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Highway and street lighting aregenerally incorporated in the

design to illuminate the roadway to

provide seeing the silhouette.

When an object is seen darker than

the background, discernment is bysilhouette.


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Silhouette Reverse Silhouette


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The Guide

1. For expressway, the standard proposed foot-candle is 10. onresidential 1.4 fc in intermediate and 2.0 in downtown areas.

2. For sidewalks on commercial areas, the recommended level ofillumination is 1.0 fc.

3. For residential streets the value is 0.4 fc.

4. The requirements for collector road facilities fall between thosefor arterials and minor streets

5. For freeways, the uniformity ratio is set to 3:1 or 4:1. theuniformity ratio is the average illumination divided by the lowestillumination.

6. The guide also recommend the right illumination level for lowmounted bridge, railings and walls of tunnels and underpasses.


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Luminaries as Street lights has the

following Criteria1. Recommended practice: Install luminaries at 12.00 meters or

more above the roadway. Although at present, the predominantmounting height is between 7.50 and 10.50 meters.

2. When mounting is high, a more uniform illumination can bemaintained even though units are widely spaced.

3. High mounting of lights reduces the building effects of glare.4. Luminaries distribute light to a definite pattern that suits

particular conditions.

5. For a higher mounting, the spacing could be in the range of 60meters apart with fixtures mounted on both sides of the road.

6. The normal practice is to suspended the luminaries over theroadway, sometimes on cables or mast arm extended outwardfrom the road side.

7. For roadway interchanges, the trend is to mount the luminaries onhigh poles, as high as 45 meters.


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END

freeway and expressway operations

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