HomeMy WebLinkAboutA002 - Council Action Form dated November 24, 2009 ITEM # 29
DATE: 11-24-09
COUNCIL ACTION FORM
SUBJECT: ZONING ORDINANCE TEXT AMENDMENT TO AMEND LIMITATIONS ON
DRIVEWAY WIDTHS AND TO DEFINE DRIVEWAYS AND DRIVE AISLES
BACKGROUND:
The Ames Municipal Code regulates driveway widths in the Development Standards
(Article 4) of the Zoning Ordinance. The regulation imposes a maximum limit of 30 feet in
width and sets minimums of 12 feet for a one-way driveway and 20 feet for a two-way
driveway. This maximum width of 30 feet is imposed on all developments, even
commercial or industrial sites where semi-trailer movements are anticipated.
In the recent past, there have been a few instances of variances being requested and
granted by the Zoning Board of Adjustment where it has been demonstrated there is a
safety issue. Most recently, a variance to the width limitations for the proposed Petco on
Southeast 5th Street was approved by the Board, as was one for the proposed Casey's on
Stange Road.
Because the current zoning regulation lacks flexibility to address needs such as this, the
City Council referred this issue to City staff, who developed a proposed amendment to the
zoning ordinance. The proposed text amendment removes the fixed maximum driveway
width and replaces it with a table from the Design Manual of the Statewide Urban Designs
and Specifications (SUDAS). This table makes distinctions between the types of land use
and the types of street on which it is located. Land use options include Residential,
Commercial, Industrial, and Agricultural uses while street types include Major Arterial,
Minor Arterial, Collector, and Local Streets. The table specifies a minimum and maximum
width for driveways. To illustrate, this approach recognizes that the driveway needs of a
single-family home on a local street are different from those of a commercial center on an
arterial street. The standards impose the minimum width under SUDAS but allow up to the
maximum width based upon conformance to specified criteria.
The proposed text amendments differentiate between the driveway (the paved area that
leads from the street to the parking area) and the drive aisle (the portion of the parking
area on which one drives to reach a parking space). The attached drawing (Figure 1)
provides some clarification. Dimensional regulations for drive aisles remain unchanged
and continue to be regulated through Section 29.406 (9).
Table 1 of Chapter 51-4 Driveway Design Criteria of SUDAS is attached for reference.
Recommendation of the Planning &Zoning Commission. At its meeting of November
4, 2009, with a vote of 5-0, the Planning and Zoning Commission recommended approval
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of the Zoning Ordinance text amendment to amend limitations on driveway widths and
provide definitions for driveways and drive aisles.
ALTERNATIVES:
1. The City Council can adopt the proposed text amendments to Chapters 29.201 and
29.406 (10).
2. The City Council can choose to not approve the proposed text amendments to
Chapters 29.201 and 29.406 (10), and thus retain the existing language.
3. The City Council can refer this item back to staff for additional analysis or options.
MANAGER'S RECOMMENDED ACTION:
These proposed amendments resolve an issue that has been more and more apparent
during site plan reviews. Developers are forced to either seek spend time and money
requesting variances to overcome the 30-foot maximum width, or else to narrow driveways
with the resultant conflicts of long trucks attempting to negotiate tight turns. These conflicts
include a truck having to swing left into an adjacent lane before making a right turn,
dragging the rear wheels across grass, or avoiding vehicles trying to exit as the truck
attempts to enter. These conflicts can lead to accidents or, at the least, driver frustration
and damage to abutting sod landscaped areas.
The proposed amendments rely on the design manual of the Statewide Urban Design and
Specifications (SUDAS), coordinated by the Institute for Transportation at Iowa State
University. SUDAS has been adopted by many communities in Iowa, including Ames. The
explicit adoption of the Design Manual allows it to be incorporated into the zoning code,
giving it the force of law as staff reviews site development plans. The proposed
amendment allows the City Traffic Engineer to determine, within the range allowed by
SUDAS and according to criteria specified in the zoning code,whether a width greaterthan
the minimum is appropriate. A driveway width greater than the maximum allowed would
still need to seek a variance.
These proposed amendments have a narrow focus and seem to readily resolve a recurring
development hurdle. Therefore, it is the recommendation of the City Manager that the City
Council approve Alternative #1 , adopting the proposed text amendments to Chapters
29.201 and 29.406 (10).
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PROPOSED AMENDMENTS
29.201 DEFINITIONS
(213) Drive Aisle: That portion of the parking area parking lot or parking structure not
intended for parking but which provides access to parking spaces or vehicular circulation in
or through a parking area, parking lot, or parking structure.
(214) Driveway: The vehicular access way from a public or private street or alley to a
parking area, parking lot, or parking structure.
29.406(10) Driveways.
Driveways fer all parking faGilities must be a minimum of 12 feet wide fOF GRe Way traffdG-
and 20 feet wode for 2 way traffmG. Driveways ansles may not eXGeed 30 feet in width.
Driveways must be designed to min imi o r i irh GUtS.
Driveways to all parking facilities shall be designed to promote safety and access
management while providing convenient access to adjoining properties.
Driveway width and design characteristics shall be as specified in the Design Manual of the
Statewide Urban Design and Specifications (SUDAS) as adopted by the City of Ames.
Driveway width shall be the specified minimum unless the City Traffic Engineer approves a
wider driveway width (not to exceed SUDAS maximum) based upon either of the following
criteria:
a. The extra driveway width is necessary to accommodate design dimension
characteristics of vehicles that use the site; or
b. The extra driveway width is necessary to resolve concerns over safe approach and
volume of traffic entering and exiting the site.
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Figure 1
Parking Area Drive aisles
Driveway
Property line
Street or Highway
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Table 1 of Chapter 51-4 Driveway Design Criteria of SUDAS
51-4-Drii-ei%av DesiEn C riteria
Table 1: Driveway dimensions
(all dimensions in feet)
Dimension
Reference Mai orihincipal Aitefial Street NiinarArterial Street
See Section 5.72. Resi- Com- Indus- AO-n- Resi- Com- Indus- A
F4ure 14) dential mercial trial ctIural dendal mercial trial Cultural
Entrance Type- C B 3 C C B B C
(a)Width W
Milli3MM 15 24 24 20 15 24 24 20
Maximum 30 45 45 3 30 45 45 30
(b)Righ-,rum Padius-'
Micinnun R 10 10 25 25 10 10 25 25
-Maxinum, 25 35 50 35 25 35 50 35
(c)Lin.Acute Akele' A 60° 700 701, 700 60" 700 700 14V
Preferred Acute Angle 901� 90, 900 900 90c, 90" 900 9W
(X)Ifin.Pavement Thicknesi T 6 in 7 in i
9 in 9 in 6 in 6 in 7 in 6 in
(If Faved) (if
paved)
1. T)?e"A'entramce iequixes special study.
2. 3 ft Flares(T�mz7v be used Sot residential&a zricLihwal ens aces.
3. Mutitir-tan spacing iozc.comer on re:,ideut property that access to a nnaar arterial street may be adjMte-dif lot frow-aze is lind'ed
Laijer lorb with larger ftowage may be 2 eqtfix ed on cwnei lots-
4. Any vas iation.Som 90',xill be evalua:ed on a case In,case Itrasiss. The acute angle(ineamred from the edge of:li--pavement',
is 60',
Reqifies,Special de:i_-M
Dimearion
Reference Collector(Ma�oi&-Nli=) Local Street
(See Sec't'on 5,-2, Re d Coos- Indus- Aefi- Resi- Cone- Indus- Agn-
FiZ-uL 14) dential mecial UW aLual dential mercial trial cultural
Entrance TNTe- C B B C C 13 B C
(a)I.Vidth W
111MIMIM, 10 24 24 1 C1 24 24 20
Maxinnun 24 40 45 3 24 32 40 30
(b)Rldi_-,in-11 p ad.,US2 R
.�,Iimnriuii 10 10 25 25 10 10 10 20
Maxi 25 35 50 35 15 20 30 35
(C)Min.Accti to 6o Angle A 4 70' 7V 700 60' 700 701, 70"
Preferred Acute Angle 900 9T 900 90Z 901, 900 900
0 MiLL Pavement T
Mckness 6 in 7 in 6 in 6 in 7 in 6 in
of paved) (if
1. Ty,pe"A"enhance xeqidres special study.
2. 3 ft flares(F)may be luied for residential&agricultural entrances-
3. airy variation aorn 9--Tvxill be el.-31-=ed on a case bv case bar;s, The-nnimillum acute angle(measured fromthe edge of tLe-pa-t-ement)
is d0=.
Requires special de;,m
Page Revissed- 1t1121/2009
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