The QEII bridge connecting Kent and Essex opened in 1991
Campaigners are calling for the return of special patrols that helped nervous drivers use the Dartford Crossing.
Road users unable to use the bridge or tunnels because of vertigo and claustrophobia had previously been able to be accompanied at the crossing.
The Highways Agency withdrew the help last August, to bring it "in line with similar crossings on major rivers".
The Campaign to Reinstate Assisted Dartford Crossing Escort Patrols say they been badly affected by its loss.
RADCEP member Jeffrey Goodwin said the thought of using either the tunnel or bridge without assistance left him 'petrified'.
He explained he and other drivers had been unable to use the crossings since the service had stopped.
"One in 10 people suffer from a fear of heights and you just can't change that fear," he told BBC Essex.
In a statement, the Highways Agency said the decision was made to "bring Dartford in line with similar crossings on major rivers, such as the Severn Crossing.
"Alternative ways of crossing the river are available, such as the Woolwich ferry and Blackwall tunnel, although we acknowledge taking these routes will add extra miles to journeys.
"The Highways Agency did not taken this decision lightly but would like to remind road users they have a responsibility to themselves and others to be fit to drive and to make prudent choices as to the routes they travel."
In response, Mr Goodwin said the Severn Bridge was "completely different" to the Essex to Kent connection.
"It's just a flat bridge, but this is the only place in the country where you've got a bridge in one direction and tunnels in another," he said.
"[With the Severn] you're not going up to the sky like this bridge does, so therefore you think you're going over the edge."