City of Frisco Engineering Standards

Engineering Standards
c. Minimum storage requirements are listed in Table 2.5. Storage requirements may be
increased by the City based upon actual and projected traffic demands of the properties
that will be served by the left-turn lane.
d. Left-turn lanes will be delineated by using the City’s current Pavement Markings and
Markers standard details.
e. Concrete pavers shall be required in the median where the median width is six feet (6’) or
less, back of curb to back of curb. If the median width is greater than six feet (6’), then
concrete pavers shall be required for a minimum distance of ten feet (10’) from the
median nose. See Figure 2.12.
2. Taper Length – The taper specifications for left-turn lane entrance areas are specified in
Table 2.5. The variables used for the specifications are shown in Figure 2.12.
TABLE 2.5: Minimum Left-Turn Lane Design Requirements
Type of Thoroughfare
On
Type of
Thoroughfare
At
Turn
Lane
Width(s)
(ft)
Length of
Full-Width
Storage(ft)
Taper Specifications
Length(ft) R 1 (ft) R 2 (ft)
A A, B 10 (1)(4) 150,250 (2) 200 505 505
B A, B 11 150 100 250 250
A, B
C, Residential
Collector
11 (4) 150 100 250 250
A, B D, E, F, G 11 (4) 100 (3) 100 250 250
A, B
Non-
Residential 11 (4) 150 100 250 250
Driveway
A,B,C,D,E,F,
TxDOT Road
G and Non-
Residential
See TxDOT’s Roadway Design Guide and Specifications (5)
Driveway
Frontage Road
A,B,C,D,E,F,
G and Non-
Apply Type A Thoroughfare specifications to Dallas Pkwy
Residential
Driveway
Apply TxDOT specifications to SH 121 and US 380
1. Double left-turn lanes
2. 150 feet for the inside left-turn lane; 250 feet for the outside left-turn lane
3. 150 feet of storage shall be required for gated communities.
4. Left-turn lanes that will become a future through lane shall be twelve feet (12’) in width and be square at the end
and incorporate a street header.
5. Turn lane designs on Preston Road (SH 289) shall also meet the requirements set forth in the Preston Corridor
Access Management Plan.
Section 2 – Thoroughfare Design Requirements May 2012 Page 2-21