The mishap occurred last evening when the four police personnel were returning after escorting Uttarakhand Governor Aziz Qureshi's convoy in Haridwar district, they said.
A police team rushed to the spot, extricated the injured policemen from the mangled remains of the jeep and admitted them to a hospital where head constable Natthi Singh Rana succumbed to injuries.
The condition of the three other policemen is critical and they have been referred to a hospital in Dehradun, they said, adding the truck driver has been taken into custody.