There should have been a fire extinguisher - I've noticed that even taxis have them in the back.

I suspect they were drunk and probably high; maybe some of them were insensible when the fire took hold?

It must have been a terrible experience to prevent them from escaping. I wouldn't wish it on anyone. The survivors will never forget this.

There are systems which produce a large amount of foam from a small amount of water, which can be very effective.

Another alternative would be a halocarbon system like you find in server rooms, which would save ruining the upholstery even if it terminated the passengers. It's a question of priorities...

Over here I'm assuming it would be illegal to smoke in a limo as it's the drivers place of work. Just like Taxi drivers or builders can't smoke in their cars or vans any more (legally, I'm sure some do).

Mechanical failure likely caused fatal California limo fire

(Reuters) - A mechanical failure probably sparked the deadly limousine fire that killed a bride and four of her friends as they crossed a bridge over the San Francisco Bay early last month, local media reported on Thursday.
The Lincoln Town Car they were riding in burst into flames when air springs in the rear of the vehicle somehow ruptured, setting off a chain of events that caused the fire, ABC7 News reported.
Neriza Fojas, 31, and eight female friends in the white stretch limousine were heading to a party across the San Mateo-Hayward Bridge to celebrate her upcoming wedding.
Fojas had married Carlo Moya in Las Vegas in a civil ceremony last year, but the couple had planned a church wedding in the Philippines for June 19, according to the Associated Press.
Authorities said at the time of the accident that the five women died as they tried to escape the burning limo through a small opening between the passenger compartment and the front seat.
Four other women suffered burns or smoke inhalation but survived the fire after getting out of the car when it stopped on the bridge.
The California Highway Patrol expects to release an official investigation report on the accident within two weeks, spokesman Art Montiel said.
"We're investigating everything in regard to the fire, including any problems with the vehicle," he said.
Investigators and San Mateo County District Attorney's Office plan to determine whether negligence was involved in the limousine's maintenance, according to local media. Reuters was not immediately able to reach the district attorney's office for comment.
(Reporting by Francesca Trianni; Editing by Scott Malone and Lisa Von Ahn)

An example of why I don't like cars that lock their doors when they start moving. It makes it harder to escape if something goes wrong.