This document summarizes a charrette for improving safety on Northampton Main/King Street in Northampton, MA. It discusses how overbuilt wide streets encourage speeding, which poses dangers to pedestrians. It presents research showing that narrowing streets from four lanes to three lanes can reduce collisions by up to 60% by calming traffic. The document proposes several designs to narrow King Street from 80 feet to 62 feet wide through road diets and paint changes to prioritize pedestrian safety and walkability while still accommodating traffic needs.

1. Northampton Main/King Charrette
NelsonNygaard Consulting Associates
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21. Overbuilt streets cause speeding
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22. Planning for pedestrian safety: Principles
Leaf, W. and Preusser, D. Literature Review on Vehicle Travel Speeds and Pedestrian Injuries
Among Selected Racial/Ethnic Groups, NHTSA (USA), 1999.
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23. Wide Streets Are Less Safe
Street widths and injury accident rate, graphic by Peter Swift
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24. Seattle Conversions (4 to 3 Lane)
Roadway Date ADT ADT Collision
Location Change Before After Reduction
Greenwood Ave N 24 to 10
Apr-95 11872 12427
N 80th St to N 50th 58%
N 45th Street 45 to 23
Dec-72 19421 20274
Wallingford Area 49%
8th Ave NW 18 to 7
Jan-94 10549 11858
Ballard Area 61%
Martin Luther King Jr W 15 to 6
Jan-94 12336 13161
North of I 90 60%
Dexter Ave N 19 to 16
Jun-91 13606 14949
Queen Ann Area 59%
24th Ave NW 14 to 10
Oct-95 9727 9754
NW 85th to NW 65th 28%
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25. Taking a Road Diet
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26. Seattle Conversions (4 to 3 Lane)
Roadway Date ADT ADT Collision
Location Change Before After Reduction
Greenwood Ave N 24 to 10
Apr-95 11872 12427
N 80th St to N 50th 58%
N 45th Street 45 to 23
Dec-72 19421 20274
Wallingford Area 49%
8th Ave NW 18 to 7
Jan-94 10549 11858
Ballard Area 61%
Martin Luther King Jr W 15 to 6
Jan-94 12336 13161
North of I 90 60%
Dexter Ave N 19 to 16
Jun-91 13606 14949
Queen Ann Area 59%
24th Ave NW 14 to 10
Oct-95 9727 9754
NW 85th to NW 65th 28%
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27. Greenwood Avenue: 12,000 cars per day
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28. Dexter Ave: 15,000 cars per day
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29. 45th Street in Wallingford: 20,000 cars per day
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31. EXISTING
Northern King Street – 80’ Right-of-Way 31

32. IDEAL
Middle King Street – 62’ Right-of-Way 32

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34. Conventional Development
Shop
School
P P
P
T T T T
T T T T T
TT
T
P
P
Work
Play P
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35. Mixed-Use District
Work
Shop
School
P
Play
T
T
Results:
<½ the parking
<½ the land area
¼ the arterial trips
1/6th the arterial turning movements
<¼ the vehicle miles travelled
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36. EXISTING
Middle King Street – 62’ Right-of-Way 36

37. IDEAL
Middle King Street – 62’ Right-of-Way 37

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39. EXISTING
Southern King Street – 55’ Right-of-Way 39

40. IDEAL
Southern King Street – 55’ Right-of-Way 40

41. CHANGES IN PAINT
Southern King Street – 55’ Right-of-Way 41

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60. space….
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