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8 <br />10. Access Management And Pedestrian Safety <br />Access management is usually promoted as a way to improve driving conditions for <br />motorists. Clearly, access management techniques can lead to roads and streets that <br />are dramatically safer and much easier and more pleasant to drive. However, <br />research also indicates that several key access management techniques are just as <br />valuable to pedestrians. These include: <br />• reducing the number of driveways, particularly commercial driveways, within a <br />given distance (per block or mile) <br />• providing for greater distance separation between driveway <br />• providing a safe refuge for pedestrian crossings with raised medians <br />COMMON ACCESS MANAGEMENT TREATMENTS <br />11. Driveway Grade <br />Along older urban arterial streets, it is common to find rather steep driveways with <br />grades (or slopes) of 5-10 percent or more. Driveways with steep grades were often <br />constructed to allow the driveway and connecting parking lots to drain more efficiently <br />and to save earth-moving costs. On the other hand, more recently constructed <br />arterials typically feature very gentle driveway grades. Driveway grade is an important <br />-yet often- overlooked -safety consideration. <br />The maximum practical grade for driveways varies between 8-14 percent for low- <br />volume driveways and five percent for high-volume driveways (a 30-foot long driveway <br />with a 14 percent grade would rise or fall about four feet along its length). <br />Furthermore, the maximum practical change in grade is about 12 percent. Above this <br />value, many vehicles will scrape their bumpers or other low-hanging parts on the <br />driveway, potentially causing damage to the vehicle and driveway or roadway surface. <br />While this may be the maximum practical grade, it is much safer to use a smaller <br />grade. A minimal grade (say, two percent) is still needed for drainage. <br />12. Driveway Width <br />Along older urban arterial streets, it is common to find many narrow driveways. Older <br />commercial driveway and parking lot designs tended to use ten to fifteen foot wide <br />driveways. This type of design will safely accommodate only one vehicle at a time, <br />either an entering or an exiting vehicle. Another common problem is driveways in <br />urban and rural areas that are too wide. In some cases, the driveway may have no <br />discernible boundaries or curbs. Both situations create operational and safety <br />concerns. A properly designed driveway helps turning traffic move off the roadway <br />more quickly and reduces the likelihood of crashes. <br />13. Clearing Driveways Away From Corners <br />Clearing driveways away from corners is the simplest, yet perhaps the most critical <br />access management treatment. <br />What is corner clearance? <br />Corner clearance is the minimum distance required between an intersection and an <br />adjacent driveway along an arterial road or collector street. <br />3 <br />