the design speed report semeniano

8/12/2019 The Design Speed REPORT Semeniano

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“The speed determined for design andcorrelation of the physical feature of a

highway that influence vehiclesoperation.”

“It is the maximum speed that can bemaintained over a specified section ofthe highway when weather and trafficconditions are so favorable that thedesign features of the highway govern.”



“The design speed be set to the greatestdegree possible, to satisfy the needs of

nearly all drivers both today andthroughout the road anticipated life.”



FACILITY

Design speed

URBAN Km/hr. RURAL Km/hr.

Freeway 80-95 preferred 110-95 mountainous

Arterial 64-95 but 48 in builtup areas

80-110

Collectors 48 Km./hr. See table 2-2

Local 32-48 Km./hr. See table 2-2



ClassTerrain

Average Daily Traffic

Collector 0-400 400-750 750-2000 2000-4000 Over 4000

level 60 75 75 75 90rolling 45 60 60 75 75

mountainous 30 45 45 60 60

Local 0-50 50-250 250-400 Over 400

level 45 45 60 75

rolling 30 45 45 60

mountainous 30 30 30 45



The volume of traffic.

Character of the traffic.

Speed of the traffic.

Characteristics of motor vehicles and of

the driver.



A 7.20m wide pavement has 18% less accidentcompared with pavement narrower than5.50m. wide.

A 7.20m wide pavement has 4% feweraccidents than the 6.00m wide roadway. Accident records showed no difference b/w

the 6.60m and the 7.20m. wide pavement. For the 6.00m., 6.60m. and 7.20m wide

pavement with 2.70 to 3.00m. wide shoulder,recorded accident decreases by 30%compared to 0 to .60m. wide shoulder. And20% compared with a .90 to 1.20m wideshoulder



For Two Lane Rural Highways, a 7.20mwide surface is required for safeclearance b/w commercial vehicles and

is recommended for main highways. For Collector Roadway, 6.00m wide

surface is acceptable only for lowvolume traffic including few trucks

traveling thereon.



For Local Rural Roadway, the minimumsurface width is 4.80m for a 30km/hr.design speed.

For Urban Roadway, the minimum designwidth is 3.60m although 3.00m is allowedwhere space is limited.



Or verge is defined as that portion of theroadway b/w the edge of the trafficlane and the edge of the ditch, gutter,curb or side slope. AASHTO requires thatits usable pavement width shall beestrong enough to support vehicles.



Serves as a plane for vehicles to stopwhen dissable or for some other

purposes. Road shoulder considerablyreduces road accidents.

The road capacity is decreased andaccident opportunity increases if theshoulder is too narrow or omitted in thedesign.



Shoulder should be continuous along thefull length of the roadway.It also addsstructural strength to the roadpavement.

Shoulder increases the horizontal sightdistance on curves. It reduces accident

potential when vehicle stop duringemergencies.



Outside shoulder should be paved for atleast 3.00 or 3.60m wide if truck volume is

more than 250 in the design hour(ADT).

The recommended width of left

(median) shoulder is 1.20 to 2.40m with atleast 1.20m paved.



If there are 6 or more than lanes, themedian shoulder should be 3.00m wide or

3.60m if truck volume in the design hourexceeds 250.

For arterials with ADT less than 400 the

usable shoulder witdth is fixed at 1.20mminimum, although 2.40m wide is muchpreffered.

When the design hour volume ADT exceeds400, the usable minimum shoulder width is2.40 m although 3.60m is recommended.



For Urban Arterial Road, similar shoulderwithout curb is suggested unless needed

for proposed drainage.

The width of median shoulder on four

lanes divided arterials is fixed at 90centemeters as minimum.

For six or more lanes, 2.40 to 3.00mshoulder width is recommended.



For Rural Collectors Roadway, 60cmwide graded shoulder is required forADT’s less than 400.

For ADT’s over 2000, 2.40m wide shoulderis recommended.



TOTALTRAVELWAY

SHOULDER WIDTH ROADWAYWIDTH

SPEED OFREFERENCE

14.00m 3.25 20.50 100-80-60-40

12.00m 3.25 18.50 60-40

7.00m 2.75 12.50 100-80-60-40

7.00m 2.00 11.00 80-60-40

6.70m 2.75 12.20 100-80-60-40

6.70m 2.00 10.70 80-60-40

6.00m 2.75 11.50 80-60-40

6.00m 1.50 9.00 80-60-40



THANKS FOR YOUR

COOPERATION



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the design speed report semeniano

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