GREEK GUIDELINES FOR SETTING SPEED LIMITS

B. Psarianos, S. Palaskas, Nat’l Techn. Univ. Athens, Greece N. Stamatiadis, Univ. of Kentucky, U.S.A.

SPEED LIMIT?

Speed Limit: It’s a Problem

Transportation Research Board 2006 Annual Meeting

3

See this Example Design Speed = Operating Speed = 85% Speed (as of December 2005)

On the TANGENT:

• Passenger Cars: 144 km/h in the driving middle lane (3.50m) –VIOLATION 24 km/h

• SU Trucks: 89 km/h in the driving middle lane

• Truck-Trailers: 87 km/h in the driving middle lane

• Buses: 98 km/h

Corinth-Athens Freeway, St.:57+550

Speed Limits (km/h):

120 for PCs, 80 for SU Trucks, 70 for Truck-Trailers, 90 for Buses

General Speed Limits: The easy part

Vehicle Type FREEWAYS High speed roads Other rural roads

Passenger cars 130 110 90

Buses 100 90 80

Articulated Buses 70 70 70

School Buses 80 80 60

Trucks ≤ 3500 kgr 100 90 80

Trucks > 3500 kgr 85 80 80

Semi Trailer Truck≤ 3500 kgr 80 80 70

Semi Trailer Truck> 3500 kgr 80 70 70

Motorcyclists ≥ 125 cc 130 110 90

Motorcyclists < 125 cc 80 80 70

Vehicle Type FREEWAYS

Freeways – wet pavement 110

High speed roads – wet pavement 90

Other road network – wet pavement 80

Freeways / High speed roads - Bridges 100

Freeways / High speed roads - Tunnels 100

Local Speed Limits The difficult part

King of the Road

It’s always the Driver!

By The Book

•  Driver selects his/her safe speed accordingly •  Speed Limit is set only when driver can not perceive the

safe speed (obscured road, sudden pedestrian traffic, pavement deterioration etc.)

•  Speed Limit the last measure for road engineering •  CONDITIONAL and EXCUSED Speed Limit

Who Decides?

•  Engineering Study •  Technical Team consisted by

–  The Road Director, –  Local Police, –  Technical Chamber of Greece

•  Primary Reference: OPERATING SPEED (V85) •  Use of Advisory Speed especially on Ramps for Heavy

Traffic •  Every 10 years regular reconsideration if not enforced by

accident history of specific site

Parameters? •  Grade (Speed Differential / Variance) •  Sharp curvature •  Sight Distance •  At-Grade Intersection (generally 70 km/h) •  Presence of Vulnerable road users (Children, Elderly People,

Bicyclists) •  Accident History •  Weaving Areas •  Roadside Development •  Specific Sites (Schools, Stadium, Animal Passage, etc)

For Example: Roadside Development

MAXIMUM SPEED LIMIT (KM/H)

Distance between Accesses (m)

Rural & suburban

roads

Urban roads

(Through roads)

70 350 - 60 300 - 50 ≤250 ≤250 ≤50 ≤200 ≤200

For Example: Through Traffic at Freeways

Roadway Functional Classification CROSS

SECTION TYPE

Speed Limit (km/h)

Rural Freeways /High Speed Highways divided undivided

130 120 110 100 90

Rural Roads between regions /counties divided 110 100 Rural Roads between cities/towns divided 100 90

Urban Freeway / Urban divided 90 80

For Example: Weaving Sections at Interchanges

Weaving Type Weaving Length [m] Area Comments

Speed Limit

[km/h] `

200

Rural &

Urban Cloverleaf interchange

type 100

180 80

250 Rural &

Urban between two interchanges

100 200 80 180 Urban 60

For Example: Interchange Ramps with max Cross-Slope 6%

Inner Curve

Radius (m) 35 35 115 170 250 (340)

Speed Limit (km/

h) 30 40 50 60 70 (80)

More Advisory Speeds

•  Advice drivers on probable dangerous conditions when exceeding the advisory speed limit like

•  Intersections with restricted visibility •  Narrow Bridges or One-Lane Bridges •  Downgrades greater than 6% •  Ramps especially for Heavy Vehicles •  On Crest and Sag Vertical Curves

•  It can be the operating speed or safe speed •  Accompanied with explaining sign

Conclusions

•  A modern guide to help agencies set reliable speed limits that will be obeyed •  Less necessity for enforcement •  Better acceptance by the driving population