How to Calculate Drive Times

How to Calculate Drive Times
Whether you're setting out on a cross-country road trip or simply planning your annual holiday rounds, calculating drive times can take a lot of the stress out of traveling. Fortunately, technology has afforded us numerous ways to map out our routes with relatively accurate results -- even if there's traffic. There is also an easy formula you can employ to calculate drive times manually. All you need to know is the speed limit of the roads you'll be traveling on and how far you'll be going on these roads.
 

Instructions

Difficulty: Moderately Easy

Things You’ll Need:
  • GPS system (optional)
  • GPS system (optional)
 
Step 1
Create a list of all planned stops and destinations. If possible, try to gather the precise addresses. If not, obtain as much information as possible, such as cross streets, nearby landmarks or ZIP codes.
Step 2
Estimate how long you anticipate your stops to take. Add these calculations to your overall drive time. For example, if one of your stops includes a gas station, add 10 minutes or so to your overall drive time. If it includes breaking for lunch, add half an hour.
Step 3
Organize these places in the order in which they will be visited. Naturally, it would be most convenient to start with the places geographically closest to your departure location.
Step 4
Visit online mapping Web sites like GoogleMaps.com or MapQuest.com and insert all of your locations in your perceived order. Once they're inputted, the Web site will map out all destinations, allowing you to change the order of your stops, should you find that a different order will save you more driving time and mileage. Print your final directions and drive times out.
Step 5
Enter your upcoming destination into your GPS or car navigation system. Check the route to make sure that it meets your approval, and once the route is confirmed the system will automatically calculate your drive time. Some systems that are internet-enabled may be able to provide you with real-time traffic, giving you the most up-to-date drive times.
Step 6
Consult a Thomas Guide or road map if you want to determine more precise drive times. This will result in the following formula: 60*Distance / Speed, or 60 (which is the amount of minutes in an hour), multiplied by the number of miles you will be driving at the same speed, divided by that speed limit. For example, if you're traveling 73 miles on a 65-miles-per-hour road, your equation would look like this: 60*73 / 65=67.38. This would mean that it would take you a little more than 67 minutes, or one hour and seven minutes, to reach your destination.
Step 7
Pay close attention to where your route changes, as the speed limit will likely change as well. For example, if you must travel for 13 miles on a major street with a 45-miles-per-hour speed limit after you've completed your 73-mile trek on the highway, calculate this driving distance out separately, since the travel time formula only works when the speed is fixed. Therefore, your new calculation would be: 60*13 / 45, which would equal 17.3, or a little more than 17 minutes. To calculate your total drive time, simply add the two travel times together: 67+17=84 minutes, or one hour and 24 minutes.
 

Tips & Warnings

 
If you're visiting busy cities or traveling on notoriously crowded highways Google Maps is the ideal system to use because it not only gives you drive times based on clear highways, but also how long they may take you in traffic. Google Maps also has built-in times if you're planning to walk or utilize public transportation on your trip. MapQuest is ideal for calculating drive times on seasonally closed roads and rural roads. If you're calculating drive times manually, remember to add a little cushion for traffic. For estimated drive times, you can use the following approximations, which account for minor traffic: you can cover one mile per minute on highways, one-half to three-quarters of a mile in one minute on major streets, and one-quarter to one-half of a mile per minute on residential streets. These numbers are derived by dividing the speed limit by 60.
 
If you're visiting busy cities or traveling on notoriously crowded highways Google Maps is the ideal system to use because it not only gives you drive times based on clear highways, but also how long they may take you in traffic. Google Maps also has built-in times if you're planning to walk or utilize public transportation on your trip.
 
MapQuest is ideal for calculating drive times on seasonally closed roads and rural roads.
 
If you're calculating drive times manually, remember to add a little cushion for traffic.
 
For estimated drive times, you can use the following approximations, which account for minor traffic: you can cover one mile per minute on highways, one-half to three-quarters of a mile in one minute on major streets, and one-quarter to one-half of a mile per minute on residential streets. These numbers are derived by dividing the speed limit by 60.
 
Realize that GPS and navigational systems are not foolproof. Many cases have been documented of people driving off roads or turning inappropriately because they relied more on their GPS systems and less on common sense. Though these devices can make travel aspects, such as calculating routes and drive times, more convenient, they are no substitutes to traveler's intuition.
 
Realize that GPS and navigational systems are not foolproof. Many cases have been documented of people driving off roads or turning inappropriately because they relied more on their GPS systems and less on common sense. Though these devices can make travel aspects, such as calculating routes and drive times, more convenient, they are no substitutes to traveler's intuition.

Article Written By Nellie Day

Nellie Day is a freelance writer based out of Hermosa Beach, Calif. Her work can regularly be seen on newsstands, where her specialties include weddings, real estate, food and wine, pets, electronics, architecture and design, business and travel. Day earned a master's degree in broadcast journalism from the University of Southern California.

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