Mike Smith, from Alton, and Terry Hampton, from Southampton, were travelling in the Alton-bound carriageway on Sunday night when their cars were pelted with rocks, forcing them to swerve to the side of the road and causing hundreds of pounds of damage to their vehicles.
Five youths aged between 14-15 were seen throwing the rocks before running back to the site and disappearing.
Mr Smith and Mr Hampton said the officers who arrived to deal with the incident told them there was nothing they could do because the culprits were thought to be travellers and that they were unwilling to go onto the site to make inquiries.
They say the officers, who took half-an-hour to reach the scene about a mile from the town centre, told them that it would effectively be "too much bother" to follow-up the crimes because the travellers are classed as an ethnic group.
This is despite the fact that both Mr Smith and Mr Hampton and their passengers, including a 14-year-old girl, narrowly avoided serious accidents when the rocks were thrown at their cars.
On Wednesday, Farnham police issued a statement relating to the incidents, but it failed to address the key complaints raised by Mr Smith and Mr Hampton.
In the statement Inspector Claire Pridgeon said: "This is a terribly dangerous thing to do. We would advise parents and guardians to warn their children of the potentially tragic consequences that could occur."
The half-an-hour delay was a result of three separate "life-threatening incidents" said the statement. The A31 incidents were being investigated and an appeal for information had been launched.
After seeing Mr Smith's car being struck and then realising his own car was being targeted, Mr Hampton swerved to a halt and chased after the youths.
He told The Herald that he clearly saw the faces of the culprits but the officers who arrived seemed indifferent to this fact and were apparently unwilling to act on it.
The attacks on Sunday night followed two similar incidents on Saturday when two cars had their passenger side windows smashed by the rock throwers.
Mr Hampton told The Herald: "I was absolutely petrified. I saw stuff being chucked at the car in front and saw five blokes behind a bush.
"Then they threw a couple of bricks at my car and I was forced to swerved across the road before stopping - it was terrifying.
"I got out and chased the blokes across a field and eventually came to the traveller site but they had disappeared.
"Before they vanished I had a really good look at them but the police who arrived said they were worried about going onto the site, but I thought that's what we had a police force for.
"Now they've said that they are not going to take it any further. They said that if they go and talk to them then they would disappear before it goes to court.
"I wasn't frightened - I chased after them, so I've done my bit. They caused £1,400 worth of damage to my car but the police are just going to let them go - it's a total joke.
"If you or I had done this you can guarantee the police wouldn't have turned a blind eye."
Mr Smith echoed many of these comments: "The police inspected the damage to my car then said that there was nothing they could do.
"They said they didn't want to approach the travellers because it would cause further trouble with the police.
"They told us we should let the matter rest and take the issue of the damage up with our insurance companies - but surely that's not right.
"I'm still stressed about it now when I think what could have happened. My wife Nessa was in the passenger seat and the other chap had his daughter in his car.
"We were both lucky - this could have been a fatal accident. I think it's very unfair that the police have just decided to let it go."
Mr Smith, who works as a gardener for a High Court Judge, added: "I asked my employer what the penalty would be for this type of crime and he said between one and two years in prison.
"It seems that it's one set of rules for us and another for them."
Farnham police can be contacted on 01252 716262 or alternatively call Crimestoppers on 0800 555 111 anonymously.
The legal fight to remove the travellers, Page 3.