Private hire drivers say they are still on edge following the murder two years ago of colleague Mohammed Arshad.
Mr Arshad, a married father-of-three, from Selly Park in Birmingham, was asked to a collect a man from outside a school in Kings Norton on 22 July, 2009.
But he was stabbed and left to die in a Worcestershire country lane by passenger Andrew Bayliss, a debt-ridden warehouse worker.
Bayliss, 29, was found guilty of his murder and sentenced to 30 years in jail in April 2011.
Steve Hind, manager of A Cars in Kings Norton, said: "It's got a lot of the drivers very nervous."
More than 10% of his work force left the trade after the attack.
"There were a lot of drivers that got out of the business after that happened, we had 16 leave just from our place alone, and others left too."
Mr Arshad's co-worker Imran Ali said: "It could have been any of us that answered that call-out. I'm nervous picking strangers up, especially when it's dark.
"But you've got to pay the bills."
Mr Arshad, 36, had worked for the company for five years and was supporting relatives in the Punjab region of Pakistan.
His wife was also expecting their fourth child, when he was fatally stabbed.
Following his death, taxi drivers, council licensing authorities and the police set up West Midlands Taxi Forum to promote driver safety.
The forum plans to publish a 20-page booklet, with emergency numbers, safety tips and driver's rights, to be distributed by the seven council licensing authorities in the West Midlands.
Barry Sollinger, the vice chairman of the forum, said: "Drivers are very vulnerable. They are lone workers and people know they carry a lot of cash on them."
Taxi forum member Gilbert Parsons said private hire drivers were more vulnerable to attack because they had to park wherever they could, often in side streets.
There are about 8,500 licensed taxis in Birmingham, which is the second biggest group in England, outside of London.
Mr Hind said he feels the law is often too lenient on those found guilty of attacking drivers.
He said: "We had a driver last year who had his face cut and bruised and his glasses broken. He was robbed and the thief only got a £300 fine and a slap on the wrists.
"We can't even defend ourselves because we're not allowed to carry weapons in our cabs.
"You can put a wheel brace in the boot but that's no good when someone is attacking you in the front."
West Midlands Police said it took all robberies and assaults seriously and urged anyone who had been attacked to report it.
It said it was the responsibility of taxi firms to train drivers in safe practices.