1. AASHTO Subcommittee on Design Reducing Engineering Standards: Good or Bad? July 14, 2008 Marc Cote, P.E. (302) 760-2266 E-Mail: marc.cote@state.de.us 7/14/08 1 AASHTO Subcommittee on Design

2. Delaware is probably somewhat unique in that 91% of the roads in Delaware are state maintained. Delaware is probably somewhat unique in that 91% of the roads in Delaware are state maintained. Access to individual homes and streets in small subdivisions all have to be approved by my office in addition to the large subdivisions and commercial developments. Access to individual homes and streets in small subdivisions all have to be approved by my office in addition to the large subdivisions and commercial developments. Reducing Engineering Standards: Good or Bad? 7/14/08 2AASHTO Subcommittee on Design

3. 7/14/08 3 Reducing Engineering Standards: Good or Bad? Dedicating Streets to Public Use and State Maintenance Built in accordance with DelDOT’s Subdivision Manual, Standard Construction Details, and Standards and Specifications. Dedicating Streets to Public Use without State Maintenance Built in accordance with DelDOT’s Subdivision Manual, Standard Construction Details, and Standards and Specifications. but privately maintained. Private Streets Not subject to our regulations, But DelDOT still suggests developers build to our standard. AASHTO Subcommittee on Design

4. Subdivision Manual requires that subdivisions generating more than 400 vpd or 50 vph in the peak hour conduct a traffic impact study. Subdivision Manual requires that subdivisions generating more than 400 vpd or 50 vph in the peak hour conduct a traffic impact study. In addition to offsite improvements outlined in the TIS, the developer is required to improve his road frontage to meet the standards for the functional classification of the road. In addition to offsite improvements outlined in the TIS, the developer is required to improve his road frontage to meet the standards for the functional classification of the road. 4 Reducing Engineering Standards: Good or Bad? AASHTO Subcommittee on Design 7/14/08

5. 5 Reducing Engineering Standards: Good or Bad? Department of Transportation Functional Classification Map Minimum Road Section Freeway or Expressway Principal Arterial 12’ Lanes 10’ Shoulders Minor Arterial Major or Minor Collector 12’ Lanes 8’ Shoulders Local Road or Street (All roads other than Subdivision Streets not shown) 11’ Lanes 5’ Shoulders AASHTO Subcommittee on Design

6. 7/14/08 6 Reducing Engineering Standards: Good or Bad? A completed design checklist must be filled out noting that all of the required information has been included on the plans, the design criteria is met, and is in accordance with DelDOT’s Standard Construction Details and Standards and Specifications. A completed design checklist must be filled out noting that all of the required information has been included on the plans, the design criteria is met, and is in accordance with DelDOT’s Standard Construction Details and Standards and Specifications. Preliminary entrance plans shall include but are not limited to the following: traffic generation diagram, adjacent entrances, functional classification of adjacent roadway, layout of required auxiliary lanes, sight distance calculations. Preliminary entrance plans shall include but are not limited to the following: traffic generation diagram, adjacent entrances, functional classification of adjacent roadway, layout of required auxiliary lanes, sight distance calculations. AASHTO Subcommittee on Design

7. Developers are making substantial improvements to our road system and there are factors to consider: Right of way impacts – local opposition Right of way impacts – local opposition Cost of improvements vs. the cost of housing Cost of improvements vs. the cost of housing Improved roads over existing conditions Improved roads over existing conditions If improvements are too extensive, development doesn’t happen, improvement doesn’t happen If improvements are too extensive, development doesn’t happen, improvement doesn’t happen Support for economic development if it is planned Support for economic development if it is planned 7/14/08 7 Reducing Engineering Standards: Good or Bad? AASHTO Subcommittee on Design

8. Want the best product for our citizens at the best cost Want the best product for our citizens at the best cost Need solution that works, doesn’t have to be the perfect solution Need solution that works, doesn’t have to be the perfect solution Improve the existing condition Improve the existing condition Don’t compromise on safety Don’t compromise on safety 7/14/08 8 Reducing Engineering Standards: Good or Bad? AASHTO Subcommittee on Design

9. Thomas Jefferson once said that: “The first obligation of government is to provide for the safety of the people.” 9 Reducing Engineering Standards: Good or Bad? AASHTO Subcommittee on Design 7/14/08

10. 10 Reducing Engineering Standards: Good or Bad? Areas for consideration Design speed Design speed Lane width Lane width Shoulder width Shoulder width Stopping sight distance on vertical and horizontal curves Stopping sight distance on vertical and horizontal curves Vertical alignment Vertical alignment Minimum and maximum grades Minimum and maximum grades Cross slopes Cross slopes Superelevation rate Superelevation rate Horizontal clearance Horizontal clearance Vertical clearance Vertical clearance Bridge width Bridge width Structural capacity Structural capacity AASHTO Subcommittee on Design

11. 7/14/08 11 Reducing Engineering Standards: Good or Bad? Standards to be maintained: Design speed Design speed Stopping sight distance on vertical and horizontal curves Stopping sight distance on vertical and horizontal curves Vertical alignment Vertical alignment Minimum and maximum grades Minimum and maximum grades Vertical clearance Vertical clearance Bridge width Bridge width Structural capacity Structural capacity Lane width Lane width Standards considered for reduction: Standards considered for reduction: Shoulder width Shoulder width Cross slopes Cross slopes Superelevation rate Superelevation rate Horizontal clearance Horizontal clearance Bridge width Bridge width AASHTO Subcommittee on Design

12. 7/14/08 12 Reducing Engineering Standards: Good or Bad? Development Related Improvements Requiring New Rights-of-Way Development Related Improvements Requiring New Rights-of-Way Gives DelDOT ability to acquire right-of-way for projects done by others (developers) to make improvements for the public’s benefit in the interest of safety. AASHTO Subcommittee on Design

13. Design ElementDelDOT Std. Subdivision DelDOT Mobility Friendly Design Guideline Right-of –Way Width 60 feet53-60’, Includes two 10’ lanes, 1’ curb offset, 6”curb on each side, one 7’ parking lane, and 10’ planting strip and 5’ sidewalk on each side Pavement Width32 feet22’-29’, max. is two 10’ lanes, 1’ curb offset and 7’ parking lane Travel Lane Width11 feet10 feet Parking Lane WidthNone specified7 feet Horz. Curve Radius300 feet167’ for unsigned curve, 90’ for signed curve used for traffic calming Design Speed30 mph25 mph Reducing Engineering Standards: Good or Bad? 7/14/08 13AASHTO Subcommittee on Design

14. Design ElementDelDOT Std. Subdivision DelDOT Mobility Friendly Design Guideline Sidewalk warrantsNot requiredRequired on both sides of street Sidewalk widthsNone specified5 feet minimum Planting Buffer/Utility Strip None specified10 feet minimum AlleysAlleys when lot width is <50’. 20’ r/w for 12’ lane Corner radiusNone specifiedLocal to local 25’ Maximum Cul-de-sac Length 500-100 feet depending on density of development 300 feet Reducing Engineering Standards: Good or Bad? 7/14/08 14AASHTO Subcommittee on Design

15. Design ElementDelDOT Std. Subdivision DelDOT Mobility Friendly Design Guideline Block LengthNone specifiedBetween 200-500’. >500 requires a midblock crossing Intersection DesignT-Intersection at 90 degrees Roundabouts and two-way stops are preferred to signals Minimum Driveway Spacing 200 feet, narrower lots call for shared driveways 50’, narrower lots require alleys or shared driveways Minimum Driveway Width 12 feet standard,8’-16’ depending on setback of garage Tree/Obstacle Clearance Clear zone of 2’ where a barrier curb is provided Minimum of 3’ from back of curb to tree Reducing Engineering Standards: Good or Bad? 7/14/08 15AASHTO Subcommittee on Design

16. Background: International Fire Code (IFC) states “fire access road shall have an unobstructed width of at least 20 feet.” DelDOT Standards and Regulations for Subdivision Streets and Highway Access Issue: “Are existing 22’ wide streets too narrow to accommodate emergency vehicles?” “Should a 24’ section be adopted by DelDOT?”

17. Wide Streets Can encourage speeding Increase impervious area May reduce the livability of a residential street Undermine perceived pedestrian/cyclist safety Inconsistent with residential traffic patterns Higher maintenance costs Community requests for traffic calming measures Source: Arlington County, VA residential streets presentation Narrow Streets May inhibit emergency response Can constrain snow plowing operations May discourage free flowing traffic Reduce vehicular speed Can improve pedestrian and cyclist safety Reduce maintenance Less impervious area “What Fire Departments Fear” “Encourages High Speeds”

18. Subdivision Street Type 1-With Curb (Emergency Vehicle and Standard Vehicle) Sidewalk 5’ Grass Strip 3’ Curb 2’ Lane11’ Lane11’ Sidewalk 5’ Grass Strip 3’ Curb 2’ Gutter Pan 11” Gutter Pan 11” Fire Engine 9.5’ (mirror to mirror) Pickup Truck 6.6’ Source: DelDOT Standards and Regulations for Subdivision Streets and State Highway Access Graphics by DelDOT Division of Planning Existing DelDOT Standards

19. Subdivision Street Type 1-With Curb w/ 11’ Lanes (Emergency Vehicle and Standard Vehicle) Graphics by DelDOT Division of Planning Top View Subdivision Street Type 1-With Curb w/ 12’ Lanes (Emergency Vehicle and Standard Vehicle) Existing DelDOT Standards w/parking both sides of street Proposed DelDOT Standards w/parking both sides of street Top View

20. Graphics by DelDOT Division of Planning Front View Subdivision Street Type 1-With Curb w/ 11’ Lanes (Emergency Vehicle and Standard Vehicle) Subdivision Street Type 1-With Curb w/ 12’ Lanes (Emergency Vehicle and Standard Vehicle) Front View Existing DelDOT Standards w/parking both sides of street Proposed DelDOT Standards w/parking both sides of street

21. Conclusion: The adoption of new 12’ lane requirements for subdivision streets that fall under the guidelines of the DelDOT Standards and Regulations for Subdivision Streets and Highway Access would enhance the ability of emergency vehicles to safely reach their intended destinations Sidewalk 5’ Grass Strip 3’ Curb 2’ Lane12’ Lane12’ Sidewalk 5’ Grass Strip 3’ Curb 2’ Gutter Pan 11” Gutter Pan 11” Proposed DelDOT Standards Graphics by DelDOT Division of Planning

22. 7/14/08 22 Reducing Engineering Standards: Good or Bad? AASHTO Subcommittee on Design