Department of Public Works
Hasley I-5 Interchange Project (Transportation)
The project reconstructed and reconfigured the existing interchange at the intersection of I-5 and Hasley Canyon Road located in the northwest of the City of Santa Clarita in Los Angeles County. As a result of planned commercial/industrial developments and transportation improvement projects, the existing I-5/Hasley canyon Road intersection was expected to experience significant increases in traffic. Newhall Land and Farming Company (a major land owner and developer within the project area), the County of Los Angeles, and Caltrans recognized the need to provide for future development and projected increases in traffic, to improve circulation in the area, and to enhance safety at this intersection. To accomplish these objectives, the project partners proposed to reconfigure the interchange by replacing the Hasley Canyon Road overcrossing, modifying the existing ramp and improving The Old Road and Hasley Canyon Road intersection which was proximate enough to the interchange on the west side to be considered part of the interchange.
EnvISIon Quality of Life
The project scored 53 out of a possible 166 points in this category. This project widened the I-5 overpass, added freeway ramps and modern roundabouts to increase the capacity and to improve the operation and efficiency of this interchange. This was done to accommodate future growth in the area while minimizing impacts on surrounding properties. By replacing the traffic signal at Hasley Canyon Road and The Old Road with a modern roundabout, delays to motorists were minimized and severity of collisions reduced. The project also incorporated landscaping providing aesthetic and environmental improvements to the interchange. This contributes greatly to the quality of life of current and future users.
EnvISIon Leadership
The project scored 37 out of a possible 121 points in the Leadership category. While there was no organization level commitment for sustainability at the time of project inception, several elements were incorporated that promote sustainability. The use of modern roundabouts over traditional traffic signals reduces energy consumption by vehicles and eliminates need for electrical energy used by traffic signals, resulting in a more sustainable interchange. A retention basin was also constructed to capture and percolate stormwater run-off originating from the project site. Other leadership elements incorporated into this project include engaging the community and stakeholders to provide input and buy off on the scope. Infrastructure integration was accomplished by a design that took into account future growth and the project team also developed a working plan for long term maintenance. A lack of organizational level commitment to sustainability during project development did not provide an opportunity for the establishment of project management systems that could seek to improve sustainable performance by pursuing things such as by-product synergy opportunities or even addressing conflicting regulations and policies that create barriers to implementing sustainable infrastructure.
EnvISIon Resources Allocation
The project scored 20 out of a possible 162 points in the Resource Allocation category. This was the poorest performing category of all the categories. The primary reason for the low score was because no analyses were performed to determine things like embodied energy, sustainable practices of suppliers, amount of excavated materials taken off-site, or the use of fresh water. A secondary reason was the lack of project management systems that could identify opportunities to use regional materials to reduce transportation costs, and specifying the use greywater, recycled water or stormwater to reduce the consumption of fresh and potable water. Some points were obtained from use of 5-20 percent of recycled materials and diversion of waste from landfills by re-using approximately 25 percent of waste materials at other job sites. Credit was also claimed for the reduction in energy consumption provided by the use of modern roundabouts as an alternative to traffic signals.
EnvISIon Natural World
The project scored the highest in this category collecting 91 out of a possible 203 points. The primary reason for this is that the improvements were constructed on the existing interchange footprint with little additional impact to previously unimproved land. Because the land the existing interchange utilized was zoned as public service facilities and floodway/flood plain, points were received for the preservation of prime farmland. The project also scored strongly in its management of stormwater by incorporating a retention basin that collects most of the run-off from the sites and infiltrates it into the ground recharging the groundwater. Filters and other measures were also used to protect the surface water in Castaic Creek.
EnvISIon Climate and Risk
The project scored 43 out of a possible 116 points in this category. Reduction of air pollutant emission was a strong performing element of this category. This is because the improvements greatly improve the flow of traffic through this interchange reducing vehicle emissions and improving air quality to a level higher than the pre-project condition. Maximum points were also awarded to preparedness for short term hazards through the restoration of wetland improvements part of the project. No life-cycle carbon assessment was performed to provide the opportunity to claim credit for the reduction of green house gases. There was also no climate impact assessment performed to claim any credit for assessing climate threat. As a result of incorporating modern roundabouts into the design, the project could claim points for innovation, as modern roundabouts are considered innovative treatments that have yet to acquire mainstream acceptance. Roundabouts benefit the environment by reducing vehicle emissions and using less energy.
EnvISIon Overall Rating
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