Problem ask for saturation flow rate in a 4 way intersection. Pretty straightforward execpt the new 2010 HCM makes things interesting.
Looks like the formula in the 2010 HCM has changed for lane width adjustment. Exh. 18-13 gives an adjustment factor for lane width fw of 1.0 for lanes between 10.0' and 12.9' wide. From my reference books that all used the 2000 HCM, the lane width adjustment was calculated using 1+(w-12/12). This changes the answer and caused me to get the problem wrong.
I used the formula starting on page 18-35 in the 2010 HCM. One number I can't find is the base saturation flow rate. All my reference manuals use 1900pcphpl for this. I can not find this in the 2010 HCM to verify. Anybody know where this is shown? This is a heads up for you all, or the chance to let me know I'm using the wrong formula.
Thanks
Looks like the formula in the 2010 HCM has changed for lane width adjustment. Exh. 18-13 gives an adjustment factor for lane width fw of 1.0 for lanes between 10.0' and 12.9' wide. From my reference books that all used the 2000 HCM, the lane width adjustment was calculated using 1+(w-12/12). This changes the answer and caused me to get the problem wrong.
I used the formula starting on page 18-35 in the 2010 HCM. One number I can't find is the base saturation flow rate. All my reference manuals use 1900pcphpl for this. I can not find this in the 2010 HCM to verify. Anybody know where this is shown? This is a heads up for you all, or the chance to let me know I'm using the wrong formula.
Thanks