I don't believe CB radio is used much anymore. I've heard truckers are using FRS frequencies? You are better off with a 2 Meter / 440Mhz ham radio (and license) for communicating with other chasers and a scanner for monitoring. A scanner can also monitor ham, FRS and CB frequencies.
I use CB radio whenever travelling. The truckers out there know every speed trap (and they still DO exist), best restaurants, and every fuel spot along the interstates and highways. Just be sure to be polite when asking for directions for this or for that. Many will reply. Either ch 18 or 19 will work in AM mode.
The best CB radio in a vehicle is the one with the best antenna. The 'best' can be seen as the longest antenna you can run with. Otherwise, you will compromise receive and transmit capabilities. Antennas with a length of 4 1/2 ft - or longer - are best! I use a 7 footer and have virtually NO problem with hearing or transmitting. Those little 3 ft jobs, the ones you might see in 'Loves' are a waste of money and are quite frankly 'very' inefficient/nearly useless.
As far as chasing goes? Practically every county across the US has amateur radio operators ('Ham' operators) that are members of ARES or RACES (amateur radio operators that form clubs and organize for emergency scenarios) and that are directly involved and in communication with that county's own Emergency Manager - if an emergency should arise. But they use a special 2 meter FM Ham radio to do this.
This requires passing a written test and a license to operate with - a permit from the FCC. If you have the Technician level license (that is the entry level license) issued, then program your radio on-the-fly to the particular frequencies they use (where the trouble is), you can also communicate with them.
Most chasers just use cell phones of those they know and the phone numbers for, and communicate that way. Or some will use GMRS or FRS radios as well because of their small size. However, a CB would have better reach, are cheap and abundant, and have almost uncluttered airwaves.
Been a Ham since 2009, when the local Emergency Manager asked me to help out the county, since I was the only storm chaser around. But he required me to obtain my FCC license before I became part of the team - officially. Well, technically speaking - a volunteer . . .