Rear-end collisions are the most common type of motor vehicle crash in the United States. The National Highway Traffic Safety Administration reports that these collisions, in which one vehicle strikes the back of another vehicle, represent nearly a third of all crashes. While few are deadly, they are a major cause of injury and property damage.

New crash avoidance technologies such as forward-collision warning systems and autonomous braking systems are becoming more widespread, and show significant potential for helping to reduce crashes. According to the National Transportation Safety Board, 90% of rear-end collisions could be avoided with just one extra second of warning time.

But such systems are no substitute for attentive, alert driving. Here are four common sense tips that can help you avoid a costly crash!

1. Maintain a Safe Following Distance

Whether you’re on highways, city streets, or rural roads, it’s important to keep a safe distance between your car and the car in front of you. A safe following distance will allow you to perceive the car in front of you braking, put your foot on your brake, and stop the car safely.

The National Safety Council and several state DMVs now recommend using the three-second rule to judge your following distance during normal daytime driving conditions:

• Choose an object on or near the road ahead to use as a fixed reference point, like a sign, a tree, or an overpass.
• As soon as the rear end of the vehicle in front of you passes the object, start counting: one thousand one, one thousand two, one thousand three.
• If you pass the object before you finish counting, you are following too closely.
• If you finish counting before you pass the object, you have established a good following distance.

The California DMV provides a quick guide on how to count out the three-second rule.

2. Increase Your Following Distance When Necessary

Depending on road conditions, three seconds might not be enough. Road conditions can make it harder to perceive hazards and harder for your brakes to stop your car safely. The California DMV recommends increasing your following distance to four or more seconds when:

• Driving on slippery roads. Roads can become slippery due to rain, snow, and ice. As fall continues, be sure to watch for fallen leaves which can become especially slippery when wet.
• Driving in low visibility. You should always increase your following distance in the dark, but seasonal weather conditions can contribute to low visibility even in the daytime. Fog, rain, and snow often limit how far you can see. Make sure your wiper blades are in good condition, and consider using a water-repellent windshield treatment. On sunny fall and winter days, glare from the sun’s low angle can temporarily blind you. Have your sunglasses at the ready, and keep both the inside and outside of your windshield free of dust and smudges for the best visibility.
• Being tailgated. If you notice a vehicle following you too closely, give yourself extra room ahead so that you won’t need to brake suddenly. Lose the tailgater as soon as you safely can by letting them pass you.
• Following a large vehicle that blocks your view of the road ahead. Hanging back will give you better visibility, and keep you out of that vehicle’s blind spots.
• Following a vehicle that may stop frequently, such as buses, garbage trucks, or postal service vehicles. Vehicles like these may also be required to stop at railroad crossings or other unexpected locations.

3. Be Aware of Your Surroundings

Scanning the road ahead of you is essential, but you should also be alert to road conditions at your sides and behind you. If you encounter an unexpected situation – debris in the road, a stalled car, an accident, or an emergency vehicle approaching from behind you – you’ll have alternative options besides slamming on the brakes, such as speeding up, changing lanes, or turning.

• Get into the habit of checking your mirrors frequently as you drive. Always look in your mirrors before you reduce your speed, including when you’re preparing to make a turn onto a side road or driveway.
• Do not stay in another driver’s blind spot, and avoid driving directly next to other vehicles. The other driver could drift or change lanes without looking and hit you, and you could get boxed in with nothing else to do but hit the brakes if you encounter a hazard in your lane.
• When you come to a stop, leave enough space between your car and the vehicle in front of you to be able to change lanes or pull over to the side of the road if necessary.

4. Be Predictable

Letting other drivers know your intentions is crucial to staying safe. It can be irritating when drivers suddenly change lanes without signaling or slow abruptly to make a turn – but worse, maneuvers like these put everyone at risk of a crash.

• Rather than stopping suddenly, slow gradually when approaching a stop sign, red light, or when preparing to turn.
• Activate your turn signal in plenty of time for your turn or lane change.
• Check your signal lights frequently to make sure they are in good working order. Make sure to include your headlights, brake lights, and turn signals in the front and rear.

Since you can’t predict what other drivers will do, using these tips to keep a “space cushion” around your vehicle will give you more time and more options to react to unexpected situations.

This is the second post of a two part series on the ongoing driving decline in the United States.

The recent decrease in driving is nearly unprecedented in American history, and has already lasted even longer than the decline experienced during World War II, when vehicle travel was limited by societal disruption and gasoline rationing.

The economic and demographic changes behind the current decline are only expected to become more pronounced in the future, so it’s time to start considering the impact this trend may have. How will the decline affect driving in the United States during the coming decades?

Effects of the Driving Decline

Reduced Gasoline Consumption

Gasoline for transportation makes up 45% of America’s total oil consumption, so changing transportation trends could have a significant impact on our international trade relationships and on the environment.

As a result of stagnant driving levels and improving fuel efficiency, gasoline consumption for transportation hit a 10-year low in 2011. This helped to bring total U.S. petroleum imports to their lowest level since 1995, and reduced carbon dioxide emissions to 1999 levels. Gasoline consumption is already expected to decline further as a result of continued improvements in fuel economy, and could be pushed even further down as miles driven decreases.

As the U.S. PIRG report suggests, decreased gasoline consumption presents an opportunity to reduce the national security challenges and economic issues associated with oil dependence on other nations, and to reduce air pollution, a major public health hazard.

But if we’re purchasing less gasoline for our cars, that also means…

Reduced Revenue from Gasoline Taxes

Every state collects taxes and fees on gasoline, which are intended to cover the costs of highways and driving. However, revenues from the gasoline tax are already insufficient to cover these expenses. In 2010, the revenue brought in from gas taxes comprised only 62% of total highway spending by all levels of government, with the rest coming from general taxpayer dollars.

Reduced gasoline use will diminish this main source of transportation funds even further. Making up the gap between gas tax revenues and the costs of necessary maintenance would require increasing state and federal gas tax rates by 53 to 58 cents per gallon or a per-mile fee on driving of about 3 cents per mile. In the scenarios considered by the U.S. PIRG report, gas tax revenues could decline by 60% to 74% by 2040.

Per-mile taxes are the most prominent proposed alternative to the gas tax. While they would reduce the impact of fuel efficiency improvements on tax revenues, further decreases in miles driven would directly affect per-mile taxes.

Traffic Congestion Could Still Increase

U.S. PIRG researchers have suggested that a decrease in miles driven per person could lead to less traffic congestion, and so far this seems to be holding true. Americans spent 421 million fewer hours stuck in traffic in 2011 than they did in 2005, the year traffic congestion peaked.

It’s unclear how booming new car sales in August will affect the total number of cars on the road, which dipped in 2009 and 2010. The U.S. car and light truck fleet is currently more than 11 years old on average, so many of these purchases may be replacing older cars rather than adding cars to the fleet.

However, congestion levels do not necessarily follow total vehicle miles driven or the total number of cars on the road. If drivers shift their travel from rural to urban areas, or to more-congested highways or times of day, it’s possible for congestion to increase even as we drive fewer miles, and even if the number of cars on the road decreases or remains the same.

So How Should We Respond?

Obtain More Information About Changing Needs

In 2011, metropolitan areas grew faster than suburban areas for the first time in decades. Public transit trips are up 10% from 2005 to 2011, and continued to rise in 2012 despite widespread service reductions and fare increases. Bicycle commuting increased 39% from 2005 to 2011, and commuting on foot increased 20% from 2005 to 2009.

But predictions made during the driving boom era, which assume a continued increase in driving, are still being used to form public policy aimed to promote car-oriented development. Taking action based on these outdated predictions can be costly.

A series of toll roads built in Southern California from 1993 to 2007 were intended to relieve traffic congestion, but have struggled to attract expected levels of traffic, resulting in raised tolls and serious financial difficulty for local government agencies and their private partner companies. The situation in Portugal, which experienced a severe recession over the past two years, is even more dire. Portugal now has four times more kilometers of roadway per person than Britain, but tolls raised to provide funds for a cash-strapped government mean that many of these roadways are now going unused.

We need to gather more information about changing travel trends to inform decision-making at all levels of government. The U.S. PIRG study recommends that the National Household Travel Survey, currently done once every 5-7 years, be conducted more often, ideally once per year.

Rethink Current Policies and Spending

Once we understand our new transportation reality, we’ll need to revisit our plans for the future. There is still a large backlog of maintenance projects that must be completed to keep our existing infrastructure usable. And since congestion may increase in some areas, we may still need to expand certain roads and highways.

But as we look to the future, we must make sure that new transportation investments will meet our needs. This means reviewing currently scheduled projects, and delaying or canceling those that are no longer relevant. Car-oriented zoning laws must also be revised to allow pedestrian, bike, and transit friendly mixed-use development.

Finally, with the potential for revenues from gas taxes and per-mile taxes to keep declining, we’ll need to seriously reconsider where our transportation funding should come from.

Have you changed your driving habits in the past few years? What prompted the change? Have you noticed any new transportation patterns in your area?

Share your experience in the comments below!