I broke one of my cardinal rules this weekend, and drove until my gas light came on.

It doesn't sound like a big deal, but driving outside Philadelphia in miles of stop and go holiday traffic with my family gave me some serious anxiety; especially after seeing all the videos of stranded motorists in Texas after Harvey blew through.

Anyway, nervously monitoring my fuel gauge while crawling along the Garden State Parkway at 5 mph made me ponder two important questions:

1. How many miles until my car ran completely out of gas?
2. Where is the nearest and cheapest gas station?

Here are short answers to both questions:

How far can you drive with your gas light on?

Generally when the light comes on you have about 2.5 gallons of gas left, which means that your car's fuel efficiency is the biggest factor in how long you can drive until your car gives out.

So, if your car or SUV gets 20 mpg, assume that you can drive about 50 miles after your gas light goes on until the sickening realization that you are totally out of gas.

Also consider that stop-and-go traffic can reduce your fuel efficiency and drop that number significantly.

Want a more specific answer? There's a handy chart on Road & Track's website that lists a more specific estimate of how many miles you can drive with your gas light on by popular car makes and models.

There is a broad range starting at about 30 miles, extending to over 70, so know your own car's estimated limit.

Where is the closest, and cheapest gas station?

So, it's not the best idea to drive limping to the closest gas station, at the mercy of whatever they are charging for gas.

This is even more important when weather or political events affect gas prices, causing unscrupulous gas station owners to jack up their prices.

The best way to avoid overpaying for gas is to look up your location at gasbuddy.com. They also have a handy app that gives you locations and prices for area gas stations.

Usually you can save 10 cents or more a gallon by checking their site and driving a little farther.

Monitor Your Car Battery Strength, Too

Gas is the most common reason car-related stop we make, but also be sure that your car is in good working order. Maybe you can "drive it home with one headlight," but car batteries are less forgiving.

Having your battery die on you is no picnic, so don't drive on an old, weak battery.

Not only is it a terrible inconvenience, but when you get towed to the nearest service center, you're at the mercy of what they want to charge you!

Unlike death and taxes, getting screwed by a mechanic is not one of life's certainties. In fact, if you are prepared, there's no reason to overpay.

Your local auto parts store, like Advance Auto Parts or AutoZone, will test your battery for free, (just one of their free services) and you can use their online coupons from your phone to save a bundle.

In summary

Knowing about how much farther you can drive when your gas light goes on is really helpful, but don't push it! It's not good to drive on fumes, and you should avoid the unnecessary risk of doing so whenever possible.

Also, the cheapest gas isn't always the best, so go with a brand name that you know, and avoid the shady "second hand" gas stations that might be selling lower quality gas.

As they say, "Life is uncertain, so eat dessert first," and always keep at least a quarter tank of gas!