Columbus Underground pointed out that 54 Share the Road warning signs and 185 shared lane pavement markings are scheduled to be installed on High Street this week from Nationwide Boulevard to Morse Road. That’s a 6.6 mile stretch, so that means there will be a sign in each direction approximately every quarter mile and a shared lane marking, also called a “sharrow,” every 376 feet on average.
The spacing for the signs seems very reasonable to me, if not too frequent, but I’m not so sure about the sharrows. I’m sure 185 markings sounds like a lot, but is it really? The typical block on High Street is 300 to 400 feet long, so that means there will be about one sharrow per block. Intuitively, I would think it might be nice to have a sharrow at the beginning and end of every block, and maybe in the middle as well. For more guidance, I went to the forthcoming edition of the Manual on Uniform Traffic Control Devices (the current edition does not cover sharrows, which are a relatively recent innovation). Here’s what it has to say about shared lane markings:
Section 9C.07 Shared Lane Marking
The Shared Lane Marking shown in Figure 9C-9 may be used to:
A. Assist bicyclists with lateral positioning in a shared lane with on-street parallel parking in order to reduce the chance of a bicyclist’s impacting the open door of a parked vehicle,
B. Assist bicyclists with lateral positioning in lanes that are too narrow for a motor vehicle and a bicycle to travel side by side within the same traffic lane,
C. Alert road users of the lateral location bicyclists are likely to occupy within the traveled way,
D. Encourage safe passing of bicyclists by motorists, and
E. Reduce the incidence of wrong-1 way bicycling.
The Shared Lane Marking should not be placed on roadways that have a speed limit above 50 km/h or 35 mph.
Shared Lane Markings shall not be used on shoulders or in designated bicycle lanes. If used in a shared lane with on-street parallel parking, Shared Lane Markings shall be placed so that the centers of the markings are at least 3.4 m (11 ft) from the face of the curb, or from the edge of the pavement where there is no curb.
If used on a street without on-street parking that has an outside travel lane that is less than 4.3 m (14 ft) wide, the centers of the Shared Lane Markings should be at least 1.2 m (4 ft) from the face of the curb, or from the edge of the pavement where there is no curb.
If used, the Shared Lane Marking should be placed immediately after an intersection and spaced at intervals not greater than 75 m (250 ft) thereafter.
It sounds like there are not enough sharrows being installed to meet the national standards in the new MUTCD. They should be no more than 250 feet apart, which would require at least 279 sharrows, probably more if you try to put them place them immediately after every intersection in addition to maintaining the spacing requirement. I would guess that we need twice as many as are currently planned.
I will grant that the referenced version of the MUTCD is technically still a draft, but since it’s expected to be approved later this year or early next year, it seems prudent to me to start designing in accordance with its guidelines. Does anyone have any additional insight into this issue?