I noticed that the SSP users are on the STARS network, and I hear periodic testing by all VDOT users. Why are they still using their conventional channels when they all have the abilities to use the STARS system.
Well, I don't listen to the old frequencies. But, Virginia Beach rescue uses 800/700 frequencies for all their traffic, yet, the radios in all the apparatus are triband radios. 800/700/155 mhz. The old frequencies are still maintained due the possibility of the trunk being knocked out by a storm or some other cause. They aren't used on an every day basis, but are there if needed. I no longer listen to them either, but I can switch back if needed. Trunking is very nice with the extra capability it adds, but there are many ways it can also fail. STARS uses internet and microwave linking to acheive what that system can do. My city also uses microwave and some internet linking also. So, there are many ways that those systems can become unusable. Once there is no repeater to use, 800/700 mhz range decreases to a line of sight system that the dispatchers can't use to alert or contact units over the large area covered by the trunk. VHF has greater range and does not depend on anything but the two radios communicating with each other.
Probably because it is cost prohibitive to put a $5000 radio in every pickup truck, dump truck, grader, etc that VDOT has. Plus portables, and let's not forget about the crappy portable coverage, so DVRS's. Dump trucks and graders don't need to talk to VSP, SSP does. Hence why VDOT stays on low band.