Road rage, drug abuse and hit-and-runs have all been deemed non-priority by Sussex Police.
Some officers are ignoring victims' demands for justice, with the investigation of some crimes never even leaving the starting blocks.
One senior officer said hundreds of crimes were being dismissed because of the way force policy was interpreted.
Another admitted there might be "grey areas" in official policy.
Chief Constable Ken Jones has promised action but the victims of these crime are growing increasingly fed up.
Marilyn Powell was the victim of road rage and a hit-and-run.
Her car was badly damaged when another vehicle ploughed into its side. Its driver swore and threatened her before driving off.
She said: "He was very frightening and refused to give me his name or insurance details.
"I was very upset and scared. Nobody came to my aid."
Badly shaken, Mrs Powell, 58, of Crescent Drive South, Woodingdean, took the man's registration details to police.
She received a stock letter, informing her Brighton police division would not be pursuing an inquiry into the incident.
The letter said: "This may be disappointing for you but I would encourage you to seek alternative means to resolve this matter to your satisfaction."
Mrs Powell's husband Ken, 64, contacted the DVLA in Swansea. It sent back details of the driver, which proved the rogue car was not even taxed at the time of the crash.
Police still refused to get involved.
Mr Powell, a retired engineer, said: "This sort of thing is putting people off going to the police. It certainly made me wonder what they are there for."
To make matters worse, Mr Powell was booked for speeding after being clocked doing 36mph along Brighton seafront days later.
He said: "That cost me a £60 fine and three penalty points, something I had never had before.
"At the same time, there was £700 damage to my car from a hit-and-run involving a vehicle that shouldn't even have been on the road. The values are all wrong."
Drug dealers and addicts have been allowed to gain a foothold in a city centre car park.
The car park at Vantage Point, near Preston Circus, Brighton, has become a haven for drug abuse, with used hypodermic needles littering the ground.
Caretaker Jim Evans has complained to police about 30 times in three years.
He said: "One constable told me: 'There's no point trying to get us down here, our bosses are creating all sorts of barriers and stopping us doing our job.'"
After calling the chief constable's office in frustration, Mr Evans was contacted by a senior policewoman, who told him: "This is not a priority."
Mr Evans, 55, himself a former policeman, said: "I don't blame the police on the street. It's clear they are being messed around by senior management.
"They are being stopped from dealing with basic crimes."
Kirsty, 27, from Burgess Hill, suffered a terrifying late-night road rage incident.
A young driver aggressively followed her car and made to ram her after she parked to call police.
She said: "When I got home I just started shaking. He didn't actually hit my car but it was very close.
"He might kill someone next time. I reported his details to police and followed it up over the next few weeks. They later told me the case had been closed the night I reported it."
Kirsty, a computer expert for an airline, said: "It was a complete waste of time. He got away with it.
"Police say lone females at night should report this type of thing but when you do, nothing happens."
Police also refused to investigate when Mick Griffiths, 49, was hit by a car which drove off.
Mr Griffiths, of North Place, Brighton, gave officers the other driver's registration number but was told the crash did not meet their criteria for investigation.
Officers said the incident was not serious enough because no one had been injured, a policy operated specifically by Brighton police division.
Police said people and money were allocated according to Force Performance Plan priorities. These focused on burglary, violent crime, car crime, reducing road deaths and cutting disorder in the community.
After transport manager Mr Griffiths' story appeared in The Argus, the chief constable pledged to reverse the policy of not investigating some crimes.
He said priorities should mean what police should do first, not that lower priority crimes did not warrant any investigation at all.
One senior police officer told The Argus hundreds of cases were being dismissed every year because they were seen as non-priority.
The officer said: "What you have got is people applying a policy without using common sense.
"People are just going into policing mode and saying, 'Sorry, we don't investigate hit-and-runs any more'. Officers are failing to use their discretion."
The officer conceded resources were limited but said: "If someone reports a crime, we have got to record it. The decision is then made whether to investigate.
"If it is a priority crime, we investigate it. Otherwise, we shouldn't look at what type of crime it is but whether it is solvable.
"We do have to prioritise but that doesn't mean we just chuck non-priority cases out of the window without looking at them."
Chief Superintendent Doug Rattray, divisional commander for Brighton and Hove, denied his officers were deliberately not investigating non-priority crimes.
He said: "There are many matters reported which are investigated and have no further leads that can be followed.
"Nothing further is done simply because there is nothing practical that can be done."
Police identified which cases could be successfully followed and which could not.
But Mr Rattray admitted: "It may be there are some grey areas."
Mr Griffiths' case was an example of this and an investigation would be opened into the hit-and-run.
He said: "We need to look at that policy again so this would be dealt with in a different way next time.
"We are interviewing Mr Griffiths again and will be doing everything possible to identify the person responsible."
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