Trail System-CS 950620MEMORANDUM �3
To: Rick Wieland, Parks Planner
From: Kenneth M. Griffin, P.E., Asst. City Manager /City Engineer
RE: Comments on the Hike and Bike Trail Master Plan
Date: June 20, 1995
Both Royal and Freeport show onroad bike trails. However, the streets for the most part are
built out. With the industrial nature of the development, the majority of the vehicles could be
trucks and semis. There could be a conflict with the vehicles and the cyclist using the same
lanes. Mockingbird Lane from Sandy Lake to Mockingbird Elementary is a narrow street
section which invariably has cars parked on both sides of the roadway the majority of the day.
When this is designated as an onroad bike trail how will vehicles and cyclist interact with the
parked vehicles? Should we be encouraging those roadways that historically have parked
vehicles on them to be used as bike trails? Portions of Parkway Blvd. also fall under this
category.
Freeport Parkway shows an off system greenwalk. This could be difficult to accomplish because
of berming and landscaping that is taking place along the Catellus property. Also, will the City
be able to acquire the additional right -of -way of 20 -24 feet in width?
The following refers to all offroad trail systems: At the June 13th Council meeting, Michael
Carr, consultant for the Master :Plan, spoke about the Burch Addition. He stated the trail needed
to go along the creek and not the property frontage because it would create conflicts with the
driveway which could make a dangerous situation. If that is really Micheal's position on offroad
trails adjacent to roadways, then I am concerned about the offroad trail systems along Freeport
Parkway, Sandy Lake Road and the southern part of Beltline and how they will interact with the
numerous existing and proposed driveways.
The ability to construct an offroad greenwalk adjacent to Sandy Lake Road near Denton Tap and
East of Maple Leaf will be limited. The section near Denton Tap is difficult because we
currently have development on the south side and proposed development on the north side which
limits our ability to acquire additional right -of -way. While we are only building a four -lane
future roadway, we are constructing dual left turn lanes at that intersection for future traffic
movements. The section east of Maple Leaf is difficult because the roadway will be
transitioning back to the south to intersect the county section of Sandy Lake at MacArthur Blvd.
As you proceed east along Sandy Lake there is also an existing open drainage facility adjacent
to Sandy Lake which will be left in that configuration in the future.
The greenwalk from Lee Elementary headed in a westward direction through the Austin Place
subdivision could be a problem. The property has already been platted without a greenwalk
location in that area. That stretch may need to be incorporat(-! as part of the on- street system
through Austin Place.
The greenwalk adjacent to Oakbend could be difficult to construct. We are currently negotiating
to purchase a lot just to construct the future street. This needs to be studied so we can require
the proper dedication in the proper place when the land develops.
Has consideration been given to future maintenance for trails along the creek areas in regards
to potential erosion? Will any trail be close enough to the existing creeks that they would need
to be cantilevered or need to have rails? This could pose a conflict with our Floodplain
Management Ordinance. On page 47, it states that single span bridges, etc. should be used in
lieu of low water crossings. We need to be cautious about placing things in the floodplain.
There will need to be floodplain studies prior to placing anything in the floodplain which could
cause an obstruction in the flow of water.
On page 25, it refers to the primary hike and bike corridor right -of -way. This indicates that the
width should be an average of 40 feet with a minimum of 20 -21 feet. Are we suggesting that
new subdivisions adjacent to creeks dedicate 40 feet of right -of -way for trail systems? Also, in
existing areas are we going to be acquiring a 40 foot right -of -way? The figure shows that the
40 foot wide area encompasses the creek. This implies that the city will be maintaining the
creeks in these areas. This is a departure from current city policy.
On page 34, it shows cutting swales on the uphill side of all trails to keep drainage from cutting
across the trail. We need to be very careful cutting the swales on the uphill side to ensure that:
(1) we're not rerouting the water to create a drainage problem elsewhere; or (2) we are aware
of the fact that at some point along the trail we need to install culverts to allow the water to get
beneath the trail.
Figure 33 on page 35 shows a clear zone that is 18 feet wide and 10 feet tall. The figure clearly
shows that anything within that 18 by 10 foot clear zone needs to be removed. This includes
any trees, low branches, etc. The clear zone allows for a 12 foot wide paving section with 3
foot shoulders on each side. I'm concerned with two issues about the clear zone: (1) clear
cutting a zone 18 feet wide will. destroy a lot of vegetation and trees along the creek areas; (2)
putting 12 feet wide concrete near the trees could damage the root systems and kill some trees
outside the clear zone. There needs to be some flexibility so we are not just clear cutting an 18
by 10 foot area.
Figure 44 on page 40 shows a speed hump 12 feet long with a 6 inch rise. This is too abrupt.
It should match the speed hump in the Speed Hump Policy that we've been working on.
On page 41, it states that a cyclist will cross the side street at 15 -20 mph. I'm concerned about
cyclists crossing side streets at 15 -20 mph. In my opinion, the cyclist should stop at the cross
streets to avoid any conflict with vehicles. The figure on page 39 for the mid -block crossing
shows stops signs for the cyclist. In my opinion, a stop sign should be used any time a cyclist
crosses any street. My experience in observing cyclist around Coppell is that they sometimes
choose to ignore the traffic control devices placed upon the streets. If we choose not to place
one at all then we could just be encouraging the cyclist to pay even less attention in crossing the
streets. This could create a tremendous safety hazard between the cyclist and the vehicles.
Figure 47 on page 43 shows a greenwalk adjacent to a roadway that has its own signal light that
is synchronized with the roadway. I think this is something that we need to avoid. Again, all
greenwalks or bike lanes crossing a street should have stop signs. My problem with signalizing
the greenwalk with the vehicular traffic is that the cyclist will see a green light and then proceed
at 15 -20 mph through the intersection, possibly not paying attention to vehicles turning right or
left towards them. Either one of those vehicles could strike the cyclist and create injury or a
fatality. I think the signalized intersection needs to be studied hard. Again my recommendation
is that there needs to be stop signs at all crossings of the street.
The figure on page 44 shows mid -block sight triangles. The sight triangles should more closely
match the sight visibility triangles in our Subdivision Ordinance. The sight triangle as shown
appears to give a wide range of visibility to the cyclist that would be crossing the street at 15 -20
mph. However, at a mid -block crossing they should be stopping prior to crossing the street.
Therefore, they need to see further down the street when they are starting from a stand still.
Figure 50 on page 45 shows sight triangles that virtually eliminate all landscaping at
intersections.
cc: Jim Witt, City Manager