i've found that the major drawback to service roads is the excessive amount of traffic in and out of adjacent parking lots that result in drivers being fixated on autos and trucks when determining if they have to right-of-way to get back on the road. they just don't "see" bicyclists. major defensive riding techniques are in order here. in other words i don't assume any driver sees me, even if they are looking me right in the eye, etc..