April 2015

  1. How many older drivers are there?

    In 2013, there were an estimated 30.1 million people 70 and older living in the United States, representing about 10 percent of the population. U.S. Census Bureau. Annual estimates of the resident population by single year of age and sex for the United Sates: April 1,2010 to July 1,2012. Washington, DC.  Based on data reported by states to the Federal Highway Administration, there were approximately 23.6 million licensed drivers 70 and older in 2013. Federal Highway Administration. 2015. Highway statistics 2013. Washington, DC. This represented approximately 78 percent of the population 70 and older and about 11 percent of drivers of all ages.

  2. How are the numbers of older drivers and their crash rates changing over time?

    Compared with drivers ages 20-69, fewer people 70 and older are licensed to drive, Federal Highway Administration. 2015. Highway statistics 2013. Washington, DC. and they drive fewer miles. Insurance Institute for Highway Safety. 2014. Unpublished analysis of data from the 2008 National Household Travel Survey and 1995 Nationwide Personal Transportation Survey. Arlington, VA. However, older people now keep their licenses longer and make up a bigger proportion of the population than in past years as baby boomers age. The number of licensed drivers 70 and older increased 30 percent between 1997 and 2012. The proportion of the 70-and-older population with licenses went from 73 percent in 1997 to 79 percent in 2012.

    According to the U.S. Census Bureau, the population 70 and older is projected to increase from 30.1 million in 2013 to 53.7 million in 2030. U.S. Census Bureau. 2014. Projections of the population by age and sex for the United States: 2015 to 2060 (Table NP2014-T9). Washington, DC. The increase in the older driver population has led to concerns about the potential effects on traffic safety. A 2003 Institute study examined historical crash rates of older drivers and projected that older drivers would become an increasing proportion of the overall crash problem, including fatal crashes. Lyman, S.; Ferguson, S.A.; Braver, E.R.; and Williams, A.F. 2002. Older driver involvements in police reported crashes and fatal crashes: trends and projections. Injury Prevention 8:116-20. Yet fewer older drivers died in crashes and fewer were involved as drivers in fatal collisions during 1998-2013 than in years past. A total of 4,115 people ages 70 and older died in motor vehicle crashes in 2013. This is 30 percent fewer than in 1997, when deaths peaked, even though the population of people 70 and older rose 23 percent during this period. The rate of fatalities per capita among older people has decreased 47 percent since 1975 and is now at its lowest level.

    Trends in passenger vehicle crash involvement rates among drivers 70 and older since the mid-1990s were examined in a 2014 Institute study. Cicchino, J.B. and McCartt, A.T. 2014. Trends in older driver crash involvement rates and fragility: An update. Accident Analysis and Prevention 72:44-54. Nationally, the fatal crash involvement rates of drivers 70 and older declined per licensed driver during 1997-2012 and per vehicle mile traveled between 1995-06 and 2008 at a faster pace than the rates for drivers 35-54 years old. The reductions were strongest among the oldest drivers (age 80 and older). During 2007-2012, the decline in fatal crash involvement rates per licensed older driver began to slow relative to middle-aged drivers. However, this did not undo earlier gains for older drivers.

    A follow-up study looked more closely at how crash involvement rates and crash survivability for older drivers changed during this period. Cicchino, J.B. 2015. Why have fatality rates among older drivers declined? The relative contributions of changes in survivability and crash involvement. Arlington, VA: Insurance Institute for Highway Safety. From 1995-98 to 2005-08, police-reported crash rates per mile traveled declined more than deaths per crash among drivers ages 75 and older, relative to drivers ages 35-54. Thus, while the reduced fatality risk of drivers ages 75 and older reflects both a lower likelihood of being involved in a crash and a greater likelihood of surviving when they do crash, reductions in crash risk played a bigger role. Improvements in crash survivability relative to middle-aged drivers were larger in side impacts than in frontal impacts.

  3. How much do seniors drive?

    Based on 2008 travel data, drivers 70 and older drove 45 percent fewer miles, on average, than drivers ages 35-54. Insurance Institute for Highway Safety. 2014. Unpublished analysis of data from the 2008 National Household Travel Survey and 1995 Nationwide Personal Transportation Survey. Arlington, VA. Older drivers are traveling more miles than they used to. From 1995-96 to 2008, average yearly mileage increased by 42 percent for drivers 70 and older, compared with a 21 percent increase for drivers 33-54.

    An Institute survey of 2,500 drivers 65 and older found that drivers with reported impairments in memory, vision, mobility and/or medical conditions such as arthritis or diabetes were more likely than other drivers to self-limit their driving by making fewer trips, traveling shorter distances, or avoiding night driving, driving on interstates or driving in ice or snow. Braitman, K.A. and McCartt, A.T. 2008. Characteristics of older drivers who self-limit their driving. Proceedings of the 52nd Annual Conference of the Association for the Advancement of Automotive Medicine. Barrington, IL: Association for the Advancement of Automotive Medicine. This supports other research showing that many older drivers self-limit their driving. Baldock, M.; Mathias, J.; McLean, A.; and Berndt, A. 2006. Self-regulation of driving and its relationship to driving ability among older adults. Accident Analysis and Prevention 38:1038-45. Ball, K.; Owsley, C.; Stalvey, B.; Roenker, D.L.; Sloane, M.E.; and Graves, M. 1998. Driving avoidance and functional impairment in older drivers. Accident Analysis and Prevention 30:313-22. Lyman, J.M.; McGwin, G., Jr.; and Sims, R.V. 2001. Factors relating to driving difficulty and habits in older drivers. Accident Analysis and Prevention 33:413-21. Stutts, J. 1998. Do older drivers with visual and cognitive impairments drive less? Journal of the American Geriatrics Society 46:854-61. Molnar, L.J. and Eby, D.W. 2008. The relationship between self-regulation and driving-related abilities in older drivers: an exploratory study. Traffic Injury Prevention 9:314-19. Some seniors do not self-regulate or adjust their driving,  Baldock, M.; Mathias, J.; McLean, A.; and Berndt, A. 2006. Self-regulation of driving and its relationship to driving ability among older adults. Accident Analysis and Prevention 38:1038-45. Ball, K.; Owsley, C.; Stalvey, B.; Roenker, D.L.; Sloane, M.E.; and Graves, M. 1998. Driving avoidance and functional impairment in older drivers. Accident Analysis and Prevention 30:313-22. even some with high levels of cognitive impairment. Stutts, J. 1998. Do older drivers with visual and cognitive impairments drive less? Journal of the American Geriatrics Society 46:854-61.

    Based on follow-up interviews in the Institute study, becoming widowed or divorced was associated with an increase in driving, whereas retiring was associated with less driving. Braitman, K.A. and Williams, A.F. 2011. Changes in self-regulatory driving among older drivers over time. Traffic Injury Prevention 12:568-75. Older drivers with worsening memory and physical mobility avoided more driving situations. However, during the three-year study period, reported changes in impairments and driving patterns were not large, perhaps because older drivers with larger changes were among those who did not complete the follow-up surveys.

  4. How do crash rates for older drivers compare with those for drivers of other ages?

    Older drivers have low rates of police-reported crash involvements per capita; their per capita fatal crash rates begin to increase at age 70.  Per mile traveled, crash rates and fatal crash rates also start increasing at about age 70. Some caution should be used when comparing crash rates per mile traveled of different age groups. Older drivers generally travel fewer annual miles than most other age groups and, similar to low-mileage drivers of other ages, they tend to accumulate much of their mileage in city driving conditions. In contrast, drivers who accumulate more miles tend to drive more on freeways or divided multilane roads, which generally have much lower crash rates than other types of roads. Hence, the elevated crash rates for older drivers when measured per mile traveled may be somewhat inflated due to the type of driving they do. Janke, M.K. 1991. Accidents, mileage, and the exaggeration of risk. Accident Analysis and Prevention 23:183-88.

    Insurance claims provide another view of crashes of all severities. Property damage liability claims are filed when an at-fault driver damages someone else's property. Collision coverage insures one's own vehicle against loss caused by a crash. Drivers ages 60-64 have the lowest rates of property damage liability claims and collision claims per insured vehicle year. Rates start increasing after about age 65, and rise above rates for middle-aged drivers at about age 80. However, older drivers' insurance claim rates are much lower than rates for the youngest drivers.

  5. To what extent does fragility contribute to older drivers' fatal crash rates?

    A study of older drivers' elevated fatal crash rates per mile traveled during 2005-08 revealed that the main factor was not seniors' over-involvement in crashes but their fragility, defined as the risk of death in a crash. Cicchino, J.B. 2015. Why have fatality rates among older drivers declined? The relative contributions of changes in survivability and crash involvement. Arlington, VA: Insurance Institute for Highway Safety. Similar results are found with more recent data for 2009-13. Fragility increases starting around middle age and continues to rise with age.

  6. How do crashes involving older drivers differ from the crashes of other drivers?

    Compared with younger drivers, senior drivers are more likely to be involved in certain types of collisions — angle crashes, overtaking or merging crashes, and especially intersection crashes. Mayhew, D.R.; Simpson, H.M.; and Ferguson, S.A. 2006. Collisions involving senior drivers: high-risk conditions and locations. Traffic Injury Prevention 7:117-24. Among passenger vehicle drivers involved in fatal crashes in 2013, multiple-vehicle crashes at intersections accounted for 40 percent of the crashes for drivers 80 and older, compared with 19 percent for drivers ages 16-59.

    Studies of senior-involved crashes have found that failure to yield the right-of-way is the most common error among seniors. Seniors are cited for this error more often than younger drivers. Mayhew, D.R.; Simpson, H.M.; and Ferguson, S.A. 2006. Collisions involving senior drivers: high-risk conditions and locations. Traffic Injury Prevention 7:117-24. In a nationally representative study of serious U.S. crashes, the most frequent error made by crash-involved drivers ages 70 and older was inadequate surveillance, which included looking but not seeing and failing to look. Cicchino, J.B. and McCartt, A.T. 2015. Critical older driver errors in a sample of serious U.S. crashes. Arlington, VA: Insurance Institute for Highway Safety. Drivers ages 70 and older were more likely than drivers ages 35-54 to make inadequate surveillance errors or to misjudge the length of a gap between vehicles or another vehicle's speed. These findings are consistent with an earlier study reporting that similar types of errors were the most common among older drivers who were at fault in intersection crashes. Braitman, K.A.; Kirley, B.B.; Chaudhary, N.K.; and Ferguson, S.A. 2007. Factors leading to older drivers' intersection crashes. Traffic Injury Prevention 8:267-74.

  7. How do age-related changes affect driving ability?

    Specific physical, cognitive and visual abilities may decline with advancing age. However, there are large individual differences in the onset and degree of functional impairments, so age alone is not sufficient information to judge driving ability. Still, functional impairments can interfere with driving and may become particularly evident in stressful or challenging driving situations such as merging or changing lanes. Several studies have shown that higher levels of physical, cognitive or visual impairment among older drivers are associated with increased risk of crash involvement. Owsley, C.; Ball, K.; Sloane, M.E.; Roenker, D.L.; and Bruni, J.R. 1991. Visual/cognitive correlates of vehicle accidents in older drivers. Psychology and Aging 6:403-15. Ball, K.; Owsley, C.; Sloane, M.; Roenker, D.; and Bruni, J. 1993. Visual attention problems as predictor of vehicle crashes in older drivers. Investigative Ophthalmology and Visual Science 34:3110-23. Johnson, C. and Keltner, J. 1983. Incidence of visual field loss in 20,000 eyes and its relationship to driving performance. Archives of Ophthalmology 101:371-75. Owsley, C.; McGwin, G., Jr.; and Ball, K. 1998. Vision impairment, eye disease, and injurious motor vehicle crashes in the elderly. Ophthalmic Epidemiology 5:101-13. Anstey, K.J.; Wood,J.; Lord,S.; and Walker, J.G. 2005. Cognitive, sensory and physical factors enabling driving safety in older adults. Clinical Psychology Review 25(1):45-65. Many older drivers also take medications, which can impair driving ability at any age but can be especially impairing for an older person.

  8. Do older drivers constitute a substantial hazard to other road users?

    In terms of fatalities, older drivers are a danger mostly to themselves and their passengers, who also typically are older and thus more vulnerable to injuries. Braver, E.R. and Trempel, R.E. 2004. Are older drivers actually at higher risk of involvement in collisions resulting in deaths or non-fatal injuries among their passengers and other road users? Injury Prevention 10:27-32. Dellinger, A.M.; Kresnow, M.; White, D.D.; and Sehgal, M. 2004. Risk to self versus risk to others: How do older drivers compare to others on the road? American Journal of Preventive Medicine 26:217-221. Langford, J.; Bohensky, M.; Koppel, S.; and Newstead, S. 2008. Do older drivers pose a risk to other road users? Traffic Injury Prevention 9:181-89. Tefft, B. 2008. Risks older drivers pose to themselves and to other road users. Journal of Safety Research 39:577-82. In 2013, 75 percent of people killed in crashes involving a driver 70 or older were either the older driver themselves (61 percent) or their older passengers (15 percent). An Institute study found that, per licensed driver, drivers 60 and older kill fewer pedestrians, bicyclists, motorcyclists and occupants of other vehicles than do drivers ages 30-59.  Braver, E.R. and Trempel, R.E. 2004. Are older drivers actually at higher risk of involvement in collisions resulting in deaths or non-fatal injuries among their passengers and other road users? Injury Prevention 10:27-32.

  9. Are rules for driver's license renewal different for older drivers?

    More than half the states have one or more renewal provisions specific to older drivers, such as shorter renewal cycles, required vision or road testing and in-person rather than mail or electronic renewal. The ages at which special regulations are required vary by state.

    See License renewal procedures.

    An Institute study of a Florida vision test requirement for drivers 80 and older found that 80 percent of those eligible to renew their licenses attempted to do so, and 7 percent of them were denied renewal because they failed the vision test. McGwin, G., Jr.; McCartt, A.T.; Braitman, K.A.; and Owsley, C. 2008. Survey of older drivers' experiences with Florida's mandatory vision re-screening law for licensure. Ophthalmic Epidemiology 15:121-27. Of those who did not seek renewal, about half said they thought they would fail the vision test.

  10. Do special regulations for driver's license renewal among older drivers affect crash rates?
    Regulations requiring in-person renewal and requiring vision testing in states where in-person renewal is not required are the only policies that are associated with lower fatality rates among older drivers, and only among drivers ages 85 and older. Tefft, B.C. 2014. Driver license renewal policies and fatal crash involvement rates of older drivers, United States, 1986-2011. Traffic Injury Epidemiology 1. For drivers 55 and older, fatality rates per licensed driver are not lower in states with laws requiring road testing, knowledge testing or shortened renewal periods for older drivers than in states without such requirements. Similarly, an Australian study found that drivers 80 and older in jurisdictions with age-based mandatory medical and/or road tests did not have lower fatal and serious injury crash involvement rates per capita or per licensed driver compared with drivers in a jurisdiction without age-based mandatory testing. Some jurisdictions with mandatory age-based testing had significantly higher fatal and serious injury crash rates than the jurisdiction without age-based testing. Langford, J.; Fitzharris, M.; Newstead, S.; and Koppell, S. 2004. Some consequences of different older driver licensing procedures in Australia. Accident Analysis and Prevention 36:993-1001.
  11. Can screening tests identify drivers with an elevated crash risk?

    The goal of driver screening is to identify people at high risk of crash involvement without falsely identifying other drivers who are not at high risk. So far, there are no tests that accomplish this goal with sufficient accuracy.

    A few states have studied tiered screening tests. California developed and pilot-tested a three-tier assessment for driver's license renewal for applicants of all ages. Camp, B.J. 2011. California’s three-tier driving-centered assessment system – outcome analysis.  Report no. CAL-DMV-RSS-11-234. Sacramento, CA: Office of Traffic Safety, California Department of Motor Vehicles. Camp, B.J. 2013. The overall program effects of California's 3-Tier Assessment System pilot on crashes and mobility among senior drivers. Journal of Safety Research 47:1-8. The first two tiers consisted of nondriving assessment tools (e.g., driving knowledge test, cognitive screening, vision tests, observation of obvious physical limitations). Most applicants failing one or more of the screening tests in the first two tiers received an educational intervention. Additionally, applicants failing both tiers had to pass an on-road driving test to renew their licenses. There was no evidence of a reduction in crash risk subsequent to participation in the pilot and only weak evidence of a reduction in subsequent at-fault injury and fatal crashes.

    A pilot study in Maryland found that drivers ages 55 and older who performed poorly on select cognitive measures were approximately 25 percent more likely than other drivers to have a subsequent at-fault crash after controlling for age, gender and annual mileage. Ball, K.K.; Roenker, D.L.; Wadley, V.G.; Edwards, J.D.; Roth, D.L.; McGwin, G., Jr.; Raleigh, R.; Joyce, J.J.; Cissell, G.M.; and Dube, T. 2006. Can high-risk older drivers be identified through performance-based measures in a Department of Motor Vehicles setting? Journal of the American Geriatrics Society 54:77-84. Although these findings suggest a general relationship between some measures of cognitive ability and crash risk, it is not clear whether the cognitive tests are sufficiently sensitive to predict future crash risk with the accuracy that would be required to justify suspending license privileges.

  12. Do states place driving restrictions on older drivers? If so, what are the effects?

    States may impose license restrictions on a driver of any age, but restrictions are imposed mostly on teenagers and older drivers. The goal of restricted licensing is to allow drivers to continue to drive in conditions that are safe for them. Restrictions on teenage drivers apply to all new licensees under a certain age because of their relative inexperience and immaturity, while restrictions on older drivers are based on individual assessment. Possible restrictions include no driving on high-speed roads, outside a certain area or at night.

    No state restricts older drivers based on age alone. The restrictions generally are based on evaluations that may be conducted when drivers apply for license renewal. Drivers may be subject to evaluations by licensing agencies based on referrals from police, physicians, family, or observations by personnel at licensing offices. States may establish policies for further testing that include vision screening, road tests, knowledge tests and/or evaluations by medical advisory boards.

    An Institute study of a restricted licensing program in Iowa found that drivers 70 and older who were identified for further testing reported more visual impairments, prescription medications and physical mobility limitations than older drivers not identified for further testing. Braitman, K.A.; Chaudhary, N.K.; and McCartt, A.T. 2010 Restricted licensing among older drivers in Iowa. Journal of Safety Research 4:481-86.  Driving exposure was reduced more among older drivers who received restrictions than among drivers who did not receive restrictions. It appeared that restrictions reinforced decisions some older drivers already had made to decrease or self-regulate their trips by driving less or reducing or eliminating driving in risky situations such as at night. The effects of restrictions on crashes are unknown. 

  13. Is driver education beneficial for older drivers?

    There is little evidence of safety benefits from education courses for older drivers, although several organizations including AARP, AAA and the National Safety council, offer such courses.

    Drivers who choose to take these courses are not representative of all drivers in their age group. Typically, they have lower crash rates before taking the course than those who do not choose to take them. This makes it difficult to design a study that separates the effects of the course from the effects due to differences between participants and non-participants. None of the evaluations of older driver improvement programs or educational initiatives has found a reduction in subsequent crash risk among participants relative to comparison groups. Janke, M.K. 1994. Mature driver improvement program in California. Transportation Research Record 1438:77-83. Kelsey, S.L and Janke, M.K. 2005. Pilot educational outreach to high-risk elderly drivers. Report no. CAL-DMV-RSS-05-213. Sacramento, CA: Office of Traffic Safety, California Department of Motor Vehicles. McKnight, A.J.; Simone, G.A.; and Weidman, J.R. 1982. Elderly driver retraining. Report no. DOT HS-806-336. Washington, DC: National Highway Traffic Safety Administration. Owsley, C.; McGwin, G.. Jr.; Phillips, J.M.; McNeil, S.F.; and Stalvey, B.T. 2004. Impact of an educational program on the safety of high-risk, visually impaired, older drivers. American Journal of Preventive Medicine 26:222-29. Nasvadi, G.E. and Vavrik, J. 2007. Crash risk of older drivers after attending a mature driver education program. Accident Analysis and Prevention 39:1073-79.

  14. Are some vehicle occupant protection features especially beneficial for older drivers?

    Some newer vehicle features that help protect occupants of all ages are especially beneficial to older occupants. Side airbags with head and torso protection have been estimated to reduce fatalities in nearside impacts by 45 percent for front seat occupants ages 70 and older, which is significantly larger than the 30 percent reduction estimated for front seat occupants ages 13-49. Kahane, C.J. 2013. Injury vulnerability and effectiveness of occupant protection technologies for older occupants and women. Report no. DOT HS-811-766. Washington, DC: National Highway Traffic Safety Administration. The safety belts in older cars tended to be less effective for older occupants than for other occupants, but modern safety belts with pretensioners and load limiters are generally equally effective for adults of all ages. The same is true of frontal airbags.

    In 2013, NHTSA proposed adding a “silver car” rating to their New Car Assessment Program to help older drivers choose vehicles that would potentially be safer for them. Given that vehicle features beneficial to older drivers also benefit drivers of other ages, it is unclear if it is possible to pinpoint vehicles that are better for older drivers than those with good safety ratings generally.

  15. How can crash avoidance technologies improve safety for older drivers?

    Vehicle technologies intended to prevent crashes may help drivers of all ages. Electronic stability control, a technology intended to increase a vehicle's stability, has been found to be highly effective in reducing single-vehicle fatal crash risk. Farmer, C.M. 2010. Effects of electronic stability control on fatal crash risk. Arlington, VA: Insurance Institute for Highway Safety. The jury is still out on many other advanced crash avoidance technologies, which haven't been around long enough for researchers to analyze their effectiveness. However, some systems look promising, based on early indications from insurance claims data. These include front crash prevention systems, especially those with autonomous braking, which are proving to be effective in reducing insurance claims. Adaptive headlights also have been found to be effective in reducing insurance claims. Adaptive headlights help drivers see better on dark, curved roads by pivoting the beam in the direction of travel. Insurance Institute for Highway Safety. 2012. They’re working: insurance claims data show which new technologies are preventing crashes. Status Report 47(5).

    Despite the potential benefits of crash avoidance technologies for helping to prevent crashes, there is some concern that systems requiring attention or responses from drivers may lead to cognitive overload or distraction from the driving task itself, especially for older drivers. Surveys of vehicle owners with crash avoidance technologies have reported some differences by age. Cicchino, J.B. and McCartt, A.T. 2015. Experiences of Dodge and Jeep owners with collision avoidance and related technologies. Traffic Injury Prevention 16:298-303. Eichelberger, A.H. and McCartt, A.T. 2014. Toyota drivers' experiences with dynamic radar cruise control, the pre-collision system, and lane-keeping assist. Arlington, VA: Insurance Institute for Highway Safety. For instance, the percentage of drivers who reported they had received multiple alerts from front crash prevention systems believed the systems helped prevent a crash declined with age, as did the percentage who reported drifting from their lanes less often with a lane departure warning and prevention system. Drivers older than 60 generally have not reported special difficulties using the technologies. In a survey of owners of Buck Lucerne vehicles with rear parking sensors, 95 percent of the respondents were older than 60 and 70 percent were older than 70. Cicchino, J.B.; Eichelberger, A.H.; and McCartt, A.T. 2015. Buick Lucerne drivers' experiences with Ultrasonic Rear Parking Assist. Traffic Injury Prevention 16:196-201. Nearly all of the owners said they would want the technology on their next vehicle.

  16. What changes in the driving environment could improve safety for older drivers?

    Much can be done to improve roadway safety for all drivers, but especially for seniors. Improving the visibility of road signs and pavement markings through lettering, size or color can be particularly important for older drivers who may have visual impairments due to macular degeneration, glaucoma, cataracts or other health factors. Intersections are a particular problem for older drivers, and countermeasures may include adding left-turn lanes and left-turn traffic signals. One study found that low-cost modifications to intersections (e.g., making traffic signals more visible, adding a dedicated left-turn lane) resulted in a 13 percent greater reduction in injury crashes per licensed driver for drivers 65 and older compared with drivers ages 25-64. Bagdade, J.S. 2004. Low cost intersection improvements reduce crashes for senior drivers. 2004 ITE Annual Meeting and Exhibit Compendium of Technical Papers (CD-ROM). Washington, DC: Institute of Transportation Engineers.

    Another approach is to reconfigure existing or new intersections as roundabouts, which reduce vehicle speeds and eliminate some of the most complicated aspects of traditional intersections. In an Institute study of intersections that were converted from stop signs or traffic signals to roundabouts, injury crashes were reduced by 76 percent. Retting, R.A.; Persuad, B.N.; Gardner, P.E.; and Lord, D. 2001. Crash and injury reduction following installation of roundabouts in the United States. American Journal of Public Health 91:628-31. However, older drivers favored roundabouts somewhat less than younger drivers. In surveys taken at least one year after the construction of new roundabouts in six communities, 65 percent of drivers ages 65 and older favored the roundabouts, compared with 70 percent of drivers 35-64 and 74 percent of drivers 18-34. Retting, R.A.; Kyrychenko, S.Y.; and McCartt, A.T. 2007. Long-term  trends in public opinion following construction of roundabouts. Transportation Research Record 2019:219-24.  An Institute study of intersections that were converted to two-lane roundabouts suggests that some older drivers may use alternate routes to avoid them. Hu, W.; McCartt, A.T.; Jermakian, J.S.; and Mandavilli, S. 2014. Public opinion, traffic performance, the environment, and safety after the construction of double-lane roundabouts. Transportation Research Record 2402:47-55. Cameras were used to observe travel on the road where the roundabouts were built and on a parallel road. After the roundabouts were built, drivers ages 70 and older were more likely to be traveling on the parallel road than on the road with the roundabouts compared with before, although the proportion of older drivers on these roads was very small. Adding features to roundabouts to make them easier to navigate such as advanced warning signs and directional signs may encourage older drivers to choose routes with roundabouts as opposed to conventional intersections. Lord, D.; Van Schalkwyk, I.; Chrysler, S.; and Staplin, L. 2007 A strategy to reduce older driver injuries at intersections using more accommodating roundabout design practices. Accident Analysis and Prevention 39:427-32.

  17. Are alternatives to driving available for older people?

    Better and more widely available alternatives to driving for older people, particularly in rural communities, are needed. In some places, public transportation or community-based systems such as van programs and volunteer drivers help older people remain mobile as they reduce or cease driving. However, in a survey of non-drivers ages 65 and older, most relied on rides from friends and family. Kostyniuk, L.P. and Shope, J.T. 2003. Driving and alternatives: older drivers in Michigan. Journal of Safety Research 34:407-14.