Not usually, for at least two reasons. First, it's illegal. FCC regulations limit the gain (signal boost) on boosters installed in moving vehicles to a maximum of 50 decibels (dB). Our smallest indoor booster model features 60dB gain.
In addition, it's virtually impossible on most vehicles to achieve the Minimum Required Separation Distance between the tower (outside) antenna and device (inside) antenna that's needed for an indoor booster to operate.
If the antennas are too close they pick up each others signals, creating a feedback loop condition called oscillation. weBoost signal boosters automatically detect this condition and immediately shut down to prevent oscillation from damaging the cellular network.
If the booster detects oscillation, it will not operate until the condition is corrected. The way to correct oscillation is to increase separation distance between the antennas until MRSD is achieved.
There is ONE EXCEPTION: an indoor booster can be installed in an RV, as long as the booster is operated only when the RV is parked. Of course the MRSD requirements still apply, but the larger size of an RV often allows MRSD to be achieved so the booster can operate.