This is exactly how I drive my car in Vancouver's awful traffic. There is really no point trying to get up any speed here as the traffic is too heavy and there are too many stop lights. The torque of my vehicle will allow me to keep up with any traffic without ever going above 2000 rpm. Added bonuses are better brake and tire life, less stress and happier passengers. The key is smoothness and watching the traffic and signals as far in advance as possible.
Another technique. I get in the car, set up my iPhone, put on my seat belt, then start the car and drive away sedately and allow the car to warm up under load. Same when stopping. I turn off the car and then close and disconnect everything. I also find a K&N air filter helps as well as synthetic oil.
Doing this, I can get 10 L / 100 km in the heaviest traffic one will ever experience in Canada. This handily beats the rating of 11.3 L / 100 km. When I first got the car, it had 8000 km on it so it was broken in. I couldn't resist gunning it all the time since it was a new toy. I saw a few tanks in the 13 L / 100 km range and one at 14, so I know these techniques work.
But...and a big BUT....when I am driving over Roger's Pass, I don't give a darn about how much fuel I am using...