Executive Summary 

HNTB has reviewed the alternatives that would create a through movement along the SR 217 corridor to the UCSB campus.  The alternatives examined resulted in an analysis of several interchange layouts along the corridor.  The preferred alternative to accomplish the overall intent of a through corridor is presented herein as Alternative 2, i.e. the Ekwill Avenue Undercrossing.  For this alternative, access to the Goleta Redevelopment area would be provided by a southbound off ramp from SR 217 in a hook ramp configuration to Kellogg Avenue northerly of the Ekwill extension.  This off ramp could be oriented such that it lines up with the entrance to the private development proposed in that area, i.e. the hotel, to avoid further traffic conflicts along Kellogg.  Ekwill would be extended from Kellogg to Ward providing access to the easterly side of SR217.  By providing the access to Ward Avenue, the northbound return traffic to SR 217 can be accommodated by using the existing SR 217 on ramp at Hollister.  To provide for the increase in traffic along Ward and at the ramp, it would be necessary to improve Ward and the ramp by providing an additional travel lane.  By taking the traffic along Ward in this manner, no adverse impacts will occur to the traffic along Hollister, one of the goals of the original redevelopment plan. Access to the redevelopment area and to the UCSB campus can be provided by maintaining the existing off ramp at Ward Ave. near Hollister and by using the Sandspit interchange too access the campus.  Eventually when funds are available, a southbound entrance ramp near Fowler could be added for more direct access to the campus from the Goleta development.

Preliminary costs for this alternative are estimated to be $4.9 million based on the information available in preparing this report. The largest portion of the cost relates to approximately 300 feet of reinforced concrete box culvert.  The size of the culvert is estimated to be triple cell, 16 foot wide by 12 foot high.  The cost for this is estimated at close to $1.1 million.  If the County is putting a program together to reconstruct this channel to improve its flood carrying capacity, there will be an opportunity to share in the overall cost of the work. This could save the implementation of Alternative 2 approximately $500,000 or more.  

As a further note on funding of the project, there appears to be an opportunity to identify the Fowler Road Extension as a low priority element of the plan and defer its construction until there is a need for the roadway.  Approximately $4.0 million was identified for the improvements along Fowler. If these funds were reallocated to the Ekwill Undercrossing Alternative, the project might possibly be in better position to receive supplemental funding.  Of key interest to this aspect is the direct benefit that can be captured from allowing access to the east side of the SR 217 corridor. If a similar development plan were to evolve east of SR217, additional revenue sources would be available. Furthermore, development on this side of SR 217 would again have an adverse effect on the flow of traffic along the SR 217 corridor.  With implementation of Alternative 2, the corridor would be preserved to provide free flow traffic through the area and making available the opportunity to access the easterly portion of Goleta.  For this circulation system to remain effective the frontage roads need to be improved.  The addition of selective ramps tying to the frontage roads will also need to be considered as traffic demand increases. 

HNTB has prepared this report in a very short time frame and recognizes there are additional elements that need to be considered before such an alternative can be implemented.  For evaluating the impacts to right-of-way, a detail study of the project site and ROW maps would need to be performed. For Alternative 2, ROW will be required along Ward Avenue between Ekwill and Hollister.  There appears to be room to widen the road in this area impacting the parkway areas in front of 4 commercial properties and a small portion of an existing orchard.

Environmental impacts for this alternative would be very similar to those described in the existing report for the redevelopment area.  The best way to assess these impacts is to compare the impacts to the original plan. Because the original plan called for at-grade intersections and Alternative 2 calls for through movement of the traffic, it is safe to assume that vehicle emission would be decreased.  Noise levels along Ward would be increased but as these are commercial property any way the impact is not expected to exceed normal sound attenuation requirements. Construction of the culverts will impact the watercourse along the flood control channel. However, the areas proposed for construction of the culvert effect existing concrete lined channel. Also, as there is a plan to improve this channel, there likely exists an environmental study that the culvert construction can be dovetailed into. There appears to be no increase in the impact to the environment as a result of this alternative.

From a traffic safety standpoint, the introduction of the at-grade intersections will increase the number of accidents along the route.  This will also be true for pedestrians and bicyclists that will have access to the expressway. The number of high-speed traffic movements being introduced to the corridor would likely lead to an increase in accidents along the corridor as well.  With the implementation of Alternative 2, there would not likely be an increase in the number of high-speed accidents along the SR 217 corridor.

The balance of the report herein will discuss the review of the existing reports and the development of the two alternatives HNTB focussed its report on.  

Traffic Impact Review

Materials reviewed in the preparation of this study included the Final Goleta Old Town Revitalization Plan (June 1998), the Proposed Final Environmental Impact Report (June, 1997), and the Project Study Reports (PSR) for the proposed Ekwill Street and Fowler Road Extensions (September, 1997).

The traffic studies in these documents consider the impacts of development at a number of key sites within the project area.  The analysis was conducted for PM peak hour conditions for the year 2007, accounting for development expected over a ten-year period.  Levels of background traffic were derived from the regional traffic model.  Intersection capacity analysis was conducted at signalized intersections along Hollister Avenue and at the proposed at-grade intersections along SR 217.

Future development in the project area will consist of residential, industrial, commercial, and mixed land uses.  Cumulative development would total about 1.16 million square feet of industrial/commercial uses and 198 residential units.  New development would use existing vacant land or replace existing underutilized buildings.

Trip generation associated with this development was estimated in accordance with the Trip Generation Manual published by the Institute of Transportation Engineers.  The net increase in tripmaking is estimated to be about 16,700 additional weekday trips related to buildout of the key sites.  The trip generation estimates were adjusted for some sites where internal or ìlinkedî trips would occur.  These practices are standard within the profession, and the trip generation estimates appear to be realistic.

Traffic distribution and assignment were prepared based on the patterns in the regional traffic model.  The preceding studies considered the scenario where Hollister Avenue remains four lanes in width, and at-grade access is provided on SR 217 at Ekwill and Fowler.  It indicates that total volume on SR 217 south of Hollister Avenue would increase to about 27,300 vpd by the year 2007, compared to 17,100 vpd in 1997.  The increase is a result of the combined effects of rising levels of through traffic, traffic from the key sites using the new at-grade intersections, and diversion of traffic from Hollister to the new intersections.

The volumes of traffic using the new at-grade intersections are estimated at 968 vehicles per hour (vph) outbound from the project area (onto northbound SR 217) and 261 vph inbound (from southbound SR 217), during the 2007 PM peak hour.  Presumably, these patterns would be reversed in the AM peak hour, but those conditions are not addressed in the EIR.  The existing PSRs for the proposed at-grade-intersections provide estimates of daily traffic volumes in the Ekwill and Fowler corridors.  The Ekwill extension will carry about 16,000 vpd west of SR 217 and the Fowler extension, about 4,300 vpd.

The intent of the Ekwill and Fowler extensions is to serve the immediate developable areas and to provide relief for the SR 217 ramp terminal intersections on Hollister Avenue.  Operating as a ìTî configuration, the SR 217/Ekwill intersection would operate at level of service (LOS) B, and the SR 217/Fowler intersection would operate at LOS A.  These conditions are characterized by delays of about 10 seconds per vehicle or less.

In the vicinity of the SR 217 intersection, the alignment of Kellogg Avenue must be adjusted so that adequate spacing can be achieved between the intersections.  The location of the Ekwill intersection also makes it necessary to remove or shorten the southbound on-ramp to SR 217 from Hollister Avenue.

Issue Identification

Review of the traffic study documentation and proposed improvement plan revealed several issues of concern related to the circulation plan:

Cumulative Development

In selecting an analysis year of 2007, the traffic study considered a ten-year period during which the key sites could reasonably be expected to develop or redevelop.  This practice is in accordance with guidelines related to traffic impact analysis.

It should be noted that the key sites represent only a portion of the developable area within the project area.  At buildout, additional development could occur within the project area apart from the identified key sites.  The 1997 EIR devoted some discussion to this buildout scenario, noting that an additional 65,000 daily trips could be generated within the project area in the long term.  No updated analysis of the cumulative development scenario was presented in the 1998 Final Plan.

Using a more modest level of about 50,000 daily trips in the cumulative development scenario, our independent analysis indicates this level of tripmaking would translate to additional traffic on SR 217 in the long term (2020).  Using the patterns shown in the earlier traffic studies, we estimate the traffic volume on SR 217 south of Hollister Avenue could reach 37,500 vpd in this scenario.  This figure is close to the stated capacity of the expressway facility (38,000 vpd).

By 2020, we estimate the ìthroughî component of travel on this portion of SR 217 would represent about 20,000 vpd. of the total SR 217 traffic. Trip delays along this corridor would increase.

While the 2007 analysis is sufficient to identify the short-term impacts of the revitalization plan, it does not adequately address the longer-term regional transportation needs.  It is appropriate that decisions concerning the role of a major corridor such as SR 217 would consider the long-term effects of added access on this facility.

Freeway/Expressway Comparison

Expressway routes represent an intermediate classification of access control between freeway and at-grade arterial streets.  Expressways typically provide access only at signalized locations that are well spaced (at least one mile apart).  In this way, optimal signal progression can be developed to maintain speeds of 55 mph.

In the proposed plan, two at-grade-signalized intersections would be located along SR 217 with a spacing of only 1500 feet.  With this close intersection spacing, it will be difficult to maintain the higher progression speeds in both directions of travel.  The higher approach speeds also pose unique problems in setting signal change intervals in these settings.  These difficulties have likely motivated the Countyís proposal to reduce the speed limit along SR 217.

Conversion of the SR 217 facility to expressway standards would also involve modifications to the southbound on-ramp from Hollister Avenue.  In the 1998 Final Plan, it is recommended to shorten the on-ramp to reflect the proposed lower design speed and proximity to the new Ekwill at-grade intersection.  The earlier 1997 EIR discussed the closure and removal of this ramp.  From a safety standpoint, it appears that removal of the ramp would be warranted.  It carries fewer than 1,700 vpd (1996 count).

Delay and Accident Costs

The conversion of SR 217 to an expressway facility will be accompanied by a reduced speed limit and the installation of at-grade signalized intersections at two locations along the route.  These measures will increase travel times for through traffic using the facility, and introduce a source of delay along the route.  There are costs associated with increases in travel times and delay.

To estimate these costs, the effects of the reduced speed limit were estimated for the portion of SR 217 south of Hollister Avenue (postmile 0.46 to 2.2).  Average delays at the signalized intersections were used to estimate additional vehicle-hours of delay.  No account was taken of the acceleration and deceleration effects of the signal.  The increment of increased travel time in 2007 is estimated to be about 377 vehicle-hours per weekday, or about 94,250 vehicle-hours annually.  In the long term, the added increment would exceed 100,000 vehicle-hours of travel.  The value of travel time is traditionally set at about $10 per person-hour in economic studies of highway benefits, and average vehicle occupancy is estimated at 1.2 persons per vehicle.  With these assumptions, the additional costs associated with the increase in travel time would range from $1.1 to $1.2 million annually.

Additional costs related to the at-grade intersections include added vehicle operating costs and added accident costs due to vehicles slowing and speeding up at the signals.  Accident rates for signalized expressway facilities are typically 50 percent higher than rates for grade-separated freeway facilities.  The County has indicated that the addition of signals will have the effect of increasing the occurrence of rear-end accidents in the corridor.  These factors will further exacerbate the costs of travel in this major corridor.

Access and Circulation Alternatives

A series of access and circulation alternatives were developed by HNTB for the SR 217 corridor that would preserve the benefits of controlled access south of Hollister Avenue.  Various concepts were evaluated with respect to traffic operation impacts, circulation patterns, potential feasibility, other impacts and project cost.

Design Objectives

The objective of this analysis is to investigate potential improvements that would maintain the advantages of access control along the SR 217 corridor.  Installation of two at-grade traffic signals in the corridor will be detrimental to the operational and safety performance of the facility.  It is acknowledged that alternative improvement programs could involve additional capital cost compared to the planned intersections.  The additional investment will provide a higher level of regional access to the project area, ensure that capacity is available for long-term growth, and reduce impacts on through traffic.

The design concepts were prepared to provide direct access to the proposed redevelopment area to and from SR 217.  The direct connections provide a stronger potential to relieve congestion along Hollister Avenue, and in particular, the intersections at the SR 217 ramps.  Design alternatives also were developed to interface with the parallel frontage roads on the east (Ward Drive) and west (Kellogg Avenue).

Concept Development

Access to freeway facilities is achieved through the use of interchange ramps that allow turning traffic to enter and leave the roadway with minimal impacts on through traffic.  Interchanges are also frequently used on expressway facilities where crossing flows of traffic exceed the capacity of at-grade intersections.  Grade separation of crossing and turning traffic provides a method of reducing conflicts at major junctions.

Interchanges on freeway facilities are optimally separated by about one mile in urban areas.  The need for a minimum spacing is determined by the crossing of vehicles entering and leaving the freeway, and profiles of vehicle acceleration and deceleration.  For grade-separated expressway facilities, these same general spacing criteria also apply when speeds are above 50 mph.

Within the project area, the location proposed for the at-grade intersection at the Ekwill Street extension is located about 2200 feet south of Hollister Avenue, and the Fowler Road intersection is another 1500 feet south.  These distances suggest the opportunities for development of a full grade-separated interchange to freeway standards are limited due to the proximity of the existing Hollister Avenue ramps.

Modification or removal of the entrance ramp from Hollister Avenue onto southbound SR 217 may make it possible to consider ramp access at the Ekwill Street extension.  The 1997 EIR examined the impact of removing this ramp and the northbound exit ramp to Ward Drive and Hollister Avenue.  The 1998 Final Plan discusses only shortening of the southbound entrance ramp to reflect a lower design speed (45 mph).  Existing traffic volume on the southbound entrance ramp is about 1,700 vpd.  This volume is sufficiently light that it could be diverted elsewhere in the network without difficulty.  In addition, removal of this leg of the ramp intersection would contribute to improved operations in the Hollister corridor.

The close spacing between the Ekwill and Fowler extensions would violate even minimum spacing criteria for an expressway facility.  Of the two streets, Ekwill is projected to carry the highest volume (about 16,000 vpd), and is located conveniently to serve the central spine of the redevelopment area.  Fowler is projected to carry only 4,300 vpd in 2007, and would not warrant classification as a major arterial.  In addition, constraints such as residential development and wetland areas would make development of ramps more difficult at the southerly location near Fowler.  For these reasons, development of design concepts focused primarily on a single access location serving the Ekwill corridor.

Grade separation along SR 217 could be accomplished by constructing the extension of Ekwill Street above the existing freeway (i.e. an overcrossing), and reconfiguring ramps to serve the new crossing.  Several constraints limit the application of this type of interchange design.  First, an overcrossing of SR 217 would cross above the parallel frontage roads due to their proximity to the freeway.  Additional local streets would then be required to connect an overcrossing to Ward and Kellogg, making the route circuitous and costly.

An alternative in this setting would consist of elevating the freeway above the Ekwill Street extension (i.e. an undercrossing).  With this approach, Ekwill Street would be extended under the freeway to connect to Ward Drive, providing traffic outbound from the redevelopment area with a route to the northbound entrance to SR 217.  The freeway mainline would be reconstructed to cross above Ekwill Street.  The existing southbound entrance from Hollister Avenue would be removed.  New ramps would be provided for the southbound exit movement at Ekwill or along Kellogg as a hook ramp configuration.  Access to the campus from the Goleta area would be by the Sandspit interchange.  This concept would be compatible with either a freeway or expressway designation of SR 217.  (See the attached Exhibit for Alternate 2.)

Other interchange types were investigated and screened for possible application in the corridor.  With a conventional diamond interchange, ramps would connect to Ekwill Street at the location of the undercrossing or overcrossing.  The close spacing of Ward Drive and Kellogg Avenue make this concept infeasible, and there are further constraints in the form of adjacent development and the stream channel to the west.  These constraints are even more limiting at the Fowler Road location.

A split interchange was conceived that would remove both the southbound entrance ramp and northbound exit ramp at Hollister Avenue, use the ramps to and from the north near Hollister and provide new ramps to and from the south at Ekwill or Fowler.  This design depends on an overcrossing or undercrossing of the freeway to connect Ward and Kellogg to serve the necessary movements, with the difficulties described above.  It also involves additional cost in the acquisition of right-of-way for the new ramps.  This concept was not developed further.

A single-point (urban) interchange was considered for the Ekwill location since this concept can be constructed with less right-of-way than a conventional diamond type.  The urban interchange features a single central intersection on the crossing street to serve all turning movements.  It depends on balance volumes of turning traffic to operate efficiently, but future turning volumes of redevelopment traffic are likely to be highly skewed to and from the west.  The urban interchange also requires higher investment in the crossing structure.  It was not considered further.

Other access alternatives were developed with a reduced level of grade separation, which might be acceptable on an expressway facility.  Much of the future demand for turning traffic will be to and from the west of SR 217.  To serve this pattern of traffic, it may be possible to provide a left-side entrance ramp onto northbound SR 217, with the southbound lanes of SR 217 elevated above this connection.  In this way, just one bridge structure would be required along SR 217 however an extensive retaining wall system would be required.  A new southbound exit ramp to Ekwill Street would be provided, and the existing southbound on-ramp from Hollister Avenue would be removed.  No changes would be made to the northbound exit ramp to Ward Drive and Hollister Avenue.  Left-side entrances are generally discourage on freeway facilities, but this concept would be compatible with a 55 mph design speed on an expressway facility.  (See the attached Exhibit for Alternate 1.)

Recommendations for Further Study

Among the various access plans and interchange alternatives, exhibits for two layouts have been developed for further study:

Alternative 1  Ekwill Ramps

This layout uses the concept of a left-side entrance onto northbound SR 217, and a new southbound exit ramp at the Ekwill extension.  The southbound mainline would be elevated above the new entrance ramp, eliminating any potential at-grade traffic conflicts.  The entrance ramp to northbound SR 217 would pass under the new bridge into the median, and merge with the northbound mainline on the left side.  The reconstructed southbound mainline is required to shift to the west slightly (8 feet) in order to provide sufficient median width for the new entrance ramp.

A new exit ramp would be developed for southbound SR 217 traffic to exit at Ekwill Street.  The existing entrance ramp to southbound SR 217 at Hollister would be removed to eliminate conflicts with the new exit ramp.  The Ekwill extension will cross the creek channel and intersect Kellogg Avenue west of the creek.

There would be no changes to the northbound exit ramp to Ward Drive and Hollister Avenue.  A barrier, delineators, ramp extension or combination of devices may be required to prevent vehicles entering northbound SR 217 on the left side from weaving across the mainline to the northbound exit ramp.

A southbound on-ramp would be provided from Kellogg Avenue near Fowler Road to replace the ramp removed from Hollister Avenue.

Alternative 2  Ekwill Undercrossing

This layout would elevate both the northbound and southbound freeway mainlines above an extension of Ekwill Street.  Ekwill would form a continuous route under the freeway connecting Ward Drive to Kellogg Avenue.  Outbound traffic from the redevelopment area would use this route to reach Ward Drive, then continue along Ward Drive to the SR 217 northbound entrance ramp at Hollister Avenue.  This pattern of traffic would require that Ward Drive be widened to provide two northbound lanes from Ekwill to Hollister.  In addition the signal at Hollister would be modified to pass two northbound lanes onto the entrance ramp, and the ramp widened to accommodate the increased demand.

A new exit ramp from southbound SR 217 would be provided in the form of a buttonhook ramp exiting to Kellogg Avenue.  The existing exit ramp to southbound SR 217 from Hollister would be removed to eliminate conflicts with the new off-ramp.  The new ramp connection to Ekwill would cross the creek channel, connect to Kellogg and proceed on Kellogg to Ekwill through two signalized intersections.

There would be no changes to the northbound off-ramp from SR 217 serving Ward Drive and Hollister Avenue.  Traffic from the Goleta area to the campus would need to use the Sandspit interchange because of the removal of the southbound entrance ramp to SR 217 at Hollister.

Cost Estimates

The construction cost estimate for the preferred alternate (Alternate 2) is approximately  $4.9 million.  The cost estimate for Alternate 1 is approximately $6.0 million.  No dollar amounts are included in the estimates for right of way.  The costs are in addition to what the County would spend on the proposed at-grade intersection at Ekwill and SR 217.  Both alternates require that a considerable length of the San Jose Creek channel be in a culvert due to the traffic movements that need to be accommodated across the channel.  This is extremely expensive as the size of the culvert is estimated to be approximately 50 feet wide by 20 feet high.  A triple barrel 16 by 12 box culvert was assumed for pricing construction costs.

The bridge in Alternative 1 will be more expensive as it will be longer to accommodate the radius required to move the traffic onto the northbound SR 217.  The need for retaining walls between the northbound and southbound travelway is also necessary and very expensive for Alternative 1. Alternative 2 does not require retaining walls to the same extent as on Alternative 1. The additional bridge cost is roughly equal to retaining wall needed in Alternative 1.  

Costs can be offset for the culvert by exploring the option of funding from the County Flood Control District.  If the channel is already programmed for improvement, a funding source exists that can drastically reduce the cost of the culvert.  This was alluded to in our discussions with the UCSB staff and needs further investigation.

Summary

HNTB recommends that further investigation and the preparation of a Project Study Report be performed for Alternative 2. At the same time, the existing traffic model for the area should be revised to determine the impacts of the proposal offered here for Alternative 2.  HNTB feels the benefits of Alternative 2 will better serve the long-term development of the area and still preserve the important access corridor to the UCSB campus, a key element in the overall development plan for the Goleta Old Town.