It’s not easy to save gas driving in crowded urban streets. Nonetheless, city drivers can increase their mileage substantially above EPA estimates by changing their driving habits in modest ways.

In city eco-driving you've got to be like a basketball player patiently waiting for scoring opportunities and then taking full advantage with lightening speed when they arise.

None of the following tips will do a miracle in itself or on every trip, but collectively you'll notice a large difference. In my MT Honda Fit I've managed to get 10 mpg above the EPA city average while driving mostly at rush hour (from 28 to 38 mpg). I’ve restricted myself to what I feel can be done safely, with courtesy to other drivers, and without being too much of a pain to implement.[1] Please comment with your own suggestions.

Let’s look in turn at: 1) making changes to your car, 2) choosing better routes, 3) driving to save gas, and 4) increasing coasting.

 

Changes to your Car

• Keep your tires at 40 psi and top them off often. Just as with a bicycle, firm tires allow you to go further on less power.[2] When replacing tires, choose those specifically rated for “low roll resistance” (LRR).[3]
• Avoid carrying around excess weight. Ditch the box of books, golf clubs, and recycling. And, since gasoline also has weight, delay filling the gas tank until the low-fuel indicator comes on. A full tank is equal to lugging around a 70 lb barbell.
• Switch to synthetic oil to decrease internal engine friction.
• Remove outside attachments that increase air drag, like flags, ski racks, and antenna toys. Keep the car washed.
• Tint your windows to reduce A/C use considerably.
• Have your mechanic perform preventive maintenance on emissions and ignition systems rather than waiting till warning lights come on. Take special note of brakes, tires, alignment, and air filter when changing oil. Track fuel efficiency so you'll immediately spot trouble.[4] 

Don't drive if you can walk or bike

• Consider adopting a "two mile minimum" rule for driving. You'll be surprised how quick and easy it is to walk or bike a mile compared to fighting traffic, and it's a great excuse for exercise.  A couple baskets on your bicycle can carry a lot of items.
  
• In urban environments it's often quicker to park some distance from your destination, and walk or bike the last part.  
• In parking lots, park away from other cars near the parking lot entrance/exit, and walk the rest. 
• If it's cumbersome to get to an errand on the left side of street, park on the right and walk across. 

Better Routes  

• Choose roads that are less crowded, where it's okay to drive slowly. Even if they have more stop signs and take more time, the coasting opportunities will make up for it and they're more relaxing. If you must take fast-paced roads, pick ones where cars tend to be in packs with lots of open space in between.

• Avoid the worst of rush hour by adjusting your schedule. Even fifteen or thirty minutes can make a noticeable difference.
• If you have a bunch of errands, do the furthest one first to warm up the engine.
  

Drive to Save Gas:

• Minimize air conditioning. Turn it off when climbing hills, accelerating, and a short time before arriving at your destination. A/C can lower your gas mileage 2-10 mpg in a small vehicle.
• Keep the rpm low. Use the highest gear that maintains speed. Higher gears utilize lower rpm and are usually more fuel efficient. Shift lower than the owner's manual recommends if you're moving steadily. Shift at higher rpm only when you need the power--for quick acceleration or going uphill.[5] Accelerate gently but briskly, getting into the higher gears quickly so you then spend more time in the efficiency "zone".
• "Drive as if you have no brakes," as the Hypermilers say. Speeding up unnecessarily and then braking hard is a habit deadly to mpg--there's no point speeding to a red light or bottleneck. Maintain steady speed, evaluating each time you throttle or brake. Avoid frequent lane changes. 
• But use the terrain: When riding through hills, accelerate down the hill and use momentum to go up--like a roller coaster. Avoid  acceleration on an uphill if you can.
  
• Try especially hard to avoid starting from a complete stop. (Remember how difficult it is to push a resting car compared to when you get it moving?)[6] Brake gradually when approaching potential slowdowns in case circumstances change, to conserve at least some momentum.
• Look ahead to anticipate traffic conditions. Look for clues: Scan the pedestrian crosswalk signals to gauge if traffic lights are "stale" and will turn before you arrive. Learn how traffic flow coming toward you and cross traffic ahead predict lights. Scan the brake lights of cars way ahead. Look for pedestrians waiting at crosswalks, turn signals, construction, school zones, speed bumps, stop signs. Scanning the distance not only saves gas, it's safer.
• Time stoplights and stop signs so you arrive just as cars are starting to move, slowing gradually if you miscalculate. If not sure when lights will change, you have more to lose by speeding up than coasting.
• When the light turns green, wait until traffic actually moves and a gap forms to begin throttle--not when you think it's going to move or when it inches forward prematurely. Wait for others to make their turns. 
• Slow is good. Cars at higher speeds have considerable "air drag" which cuts into gas mileage. (This is one of the few areas in which city driving gives you a fuel-saving advantage over highway.) Try to stay at 40 mph or below. Mileage decreases especially rapidly from 60 mph and up.[7]
• Avoid unnecessary idling.  Have your seat belts and lipstick on, CD chosen, kids satiated, windows clean, and everything "good to go" before starting ignition. Turn off engine if it's going to be more than a minute.  Avoid drive-throughs.  And don't waste excess time idling to warm your engine; modern cars need seconds not minutes before you can drive. 
• Take special care in parking lots, since they are a "worst case" involving cold engine, idling, 1st, reverse, sudden braking. Avoid the maze of congestion as much as possible--remember, this will affect you twice, once coming and once going. When you enter a parking lot, immediately scan for a spot near the exit you can coast into, ideally facing outward. This will make your exit clean and easy. (And, as a side benefit, walking a little further to your car is great exercise.)
• Some other gas-guzzling "danger zones": cold engine; 1st, 2nd, reverse gears. Until the temperature light goes off don't tax your engine: don't "force" speed, use minimal throttle, use no A/C. Don't linger in low gears more than necessary. (Pulse and glide instead--see below.)  

The Art of Coasting

• You can easily get several hundred miles per gallon while coasting in neutral, so in a stick-shift do so at every opportunity. Even short glides add up, but don't be afraid to coast much further as you get more skilled. You'll be surprised how far from the light  you can start coasting (I aim for half miles). Gently come back into gear to minimize transmission wear.[8]
• If you own an automatic, you can still gain some of the benefits by coasting in "Drive". Many modern cars shut off the fuel injectors when you glide without throttle. You won't glide nearly as far as with a manual transmission, but it's still far better mileage than normal driving. (Note: I'm not talking about driving an automatic in neutral!)
  
• Accelerate before coasting if that enables you to coast all the way to the light. Sometimes the smallest acceleration will really pay off in coasting distance; and, opposite to normal driving, the faster you're coasting the more mpg you're getting.
• Scan behind as well as ahead. To be courteous you want to coast at a speed that flows with traffic. Before shifting to neutral, decide if you have to accelerate to be at the speed cars behind will be as they catch up. Allow yourself an extended coast when you're the last one through a light or the last car in a pack.
• Take full advantage of downhill inclines to coast far and maintain speed. However, accelerate a bit on the downhill if it allows you to avoid accelerating on the uphill.
• "Pulse and glide" is an efficient technique for slow speeds and short distances like neighborhood streets and parking lots. You accelerate to slightly faster than you need, then coast as far as you can, and repeat as necessary. You can also pulse and glide to inch forward at stoplights with slight blips of the gas pedal. 
• Leave plenty of distance between you and the cars ahead in order to control your own driving style and to create coasting opportunities. This is also safer.
• Instead of mindlessly tapping brakes in reaction to the person ahead, consider shifting to neutral and being ready to brake. People tend to tap their brakes out of habit, so it's mostly a "false alarm".[9] 
• Coast the final distance to your parking spot at work and into your garage at home. With experience, you'll be surprised how far back you can begin.

See Citympg Blog for other articles and for comments.

Notes

¹ Some methods used by "hypermilers" not discussed here: drafting, engine-off-coasting, bump starting, forced auto-start, ridge riding, codfishing, grill blocking. See gassavers.org and cleanmpg.com. I have also left out tips which pertain more to freeway driving than the inner city, like rolling up windows to reduce drag and using cruise control.

2 Raising tire pressure somewhat beyond that recommended in the owner's manual appears to be safe. Never go above the pressure listed on the sidewall, but consider going up to it. For instance, the Fit owner's manual recommends 32 psi for the OEM Dunlop SP A/S31, they are rated on the sidewall at 44 psi.

3 Consumer Reports' tire reviews are a good place to start for LRR ratings. OEM tires are relatively good since auto companies pick tires that give them high epa tests. If you don't have RR info, in general the lighter and narrower the tire the better the RR. The hybrid internet forums like greenhybrid.com are another good source of information. Be sure to look at handling and tread-life ratings too, though, since many LRR tires do not brake as well or wear out quickly.

4 Other components which affect fuel efficiency: air-fuel ratio sensors, PCV, EGR, spark plugs and other emissions and ignition components. See http://oee.nrcan.gc.ca/carcare-monthly

5 In the Honda Fit in particular, the v-tec engine changes to "gas guzzler" mode with the valves open at 3400 rpm so keep that as your upper limit. The Fit engine seems to lug around 1500 rpm so use that as your bottom limit. If moving steadily you can easily shift at 3000 rpm, or even lower.

6 "During stop-and-go city driving, it's estimated that overcoming inertia is responsible for about 35% of the vehicle's resistance. Driveline friction is about 45%; air drag is about 5% and tire rolling resistance is about 15%." http://www.tirerack.com/techid=29

7 Air drag is due to front air resistance, rear air vacuum, and other turbulence. See http://auto.howstuffworks.com/477 for an explanation of drag, or this,http://www.grc.nasa.gov, http://www.atmosphere.mpg.de, Velocity airdrag507

8 For a rough estimate of mpg while coasting in a modern, small car, divide your speed in mph by 0.25. For instance, the Honda Fit uses between 0.21 and 0.32 gallons of gas per hour while idling, depending on temperature, A/C, headlight use etc. So a warm Fit coasting 35mph is getting about 167 mpg.

9 Many modern cars shut off the fuel injectors if the car is in gear with no throttle doing more than 1000 rpm, so some hypermilers like to coast in gear. While this indeed uses less gas (zero) than "coasting" in neutral, the "engine braking" effect makes it less fuel efficient in most cases. A burdensome alternative is to coast in neutral till you want to stop, then engine brake the remainder.