Design Truck recommendation for 2006, WB-40 or WB-53
Design Truck recommendation for 2006, WB-40 or WB-53
(OP)
Working in Wilmington Delaware (Urban Condition) where I have typically used WB-40 to design truck access. While recently driving along I-95, I noticed that out of 59 trucks, not including SU's or tankers, an overwhelming portion (80%) of semi-trailer trucks were marked with the number 53'. Those semi-trailer that were not marked were smaller than the 53' so I assumed that they were wb-40's. After my unofficial truck evaluation, should I now start using wb-53' for a design truck?





RE: Design Truck recommendation for 2006, WB-40 or WB-53
RE: Design Truck recommendation for 2006, WB-40 or WB-53
In NY, WB-50s are the largest vehicle that can use roads not on the list. Delaware may be different.
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"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail."
Wm. Phelps Eno, ca. 1928
RE: Design Truck recommendation for 2006, WB-40 or WB-53
RE: Design Truck recommendation for 2006, WB-40 or WB-53
I recently designed site grading and parking lot improvements to accommodate an expansion to a truck service bay at a truck stop, right of the exit ramp of I81 in PA, USA (well within the 1 mile AC refernces). The Township required, and the truck stop owners concurred, that proposed layout must accommodate a 53’ trailer and 30’ cab.
Engineering is the practice of the art of science - Steve
RE: Design Truck recommendation for 2006, WB-40 or WB-53
WB-67: Delaware's maximum legal trailer length = 53'
WB-62: Standard Vehicle as established under the 1982 Surface Transportation Assistance Act using a trailer lentgh = 48'
RE: Design Truck recommendation for 2006, WB-40 or WB-53
I think this goes back to AC's commentary. It is somewhat site (road classification) specific. Should we use the maximum size allowed on interstates for subdivision street design?
I may try to make the design work for the infrequent moving truck of this size, but I would not be concerned with the vehicle maintaining it's own lane etc. in this situation.
For state designated Arterials and Collectors and higher classification, I would certainly design with a WB-67.
RE: Design Truck recommendation for 2006, WB-40 or WB-53
But, a service bay at a truck stop where the exit deadends into a 20' high 2:1 hillside? Yes.
Engineering is the practice of the art of science - Steve
RE: Design Truck recommendation for 2006, WB-40 or WB-53
FYI, excerpt from NCHRP report 505.
Several changes in the design vehicles presented in the AASHTO Policy on Geometric Design of Highways and Streets, commonly known as the Green Book, are recommended.
Specifically, it is recommended that the current WB-15 [WB-50] design vehicle be dropped because it is no longer common on U.S. roads. The kingpin-to-center-of-reartandem
(KCRT) distance for the WB-19 [WB-62] design vehicle should be increased from 12.3 to 12.5 m [40.5 to 41 ft]. The WB-20 [WB-65] design vehicle should be dropped from the Green Book and the WB-20 [WB-67] design vehicle used in its place. In addition, a three-axle truck, the SU-8 [SU-25] design vehicle, and a Rocky Mountain
Double, the WB-28D [WB-92D] design vehicle should be added to the Green Book.
RE: Design Truck recommendation for 2006, WB-40 or WB-53
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"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail."
Wm. Phelps Eno, ca. 1928