As we were solving the station infrastructure issue, we are also working closely with several engine manufacturers to deliver the desired engines for the heavy duty truck market which are really the 12 and 13 liter engine.
The 11.9 liter Cummins Westport engine is expected to become available in the first quarter of next year and the 13 liter Navistar and Volvo engines are expected to follow in late 2013 and early 2014.
Once these engines are widely available and initial phase of the highway is complete we believe the heavy duty Class 8 truck market will begin to make the situation. This adoption should be similar to what we have seen in the refuse market over the last five years, once that market had the right end. In 2008, when the 8.9 liter Cummins Westport engine first became available, the adopted rate of natural gas engines in the refuse market went from 3% that year to close to 50% of new purchases this year.
As aside we see that the adoption rate continually increase because of the enormous fuel savings refuse top rates we were experiencing compared to these. Today we have completed construction of 22 of our highway stations and an additional 24 are under construction and 32 more are in various stages of entitlement, design and permit. We are still targeting to complete construction of about 70 natural gas truck stop stations by year end and many of the station completions will occur at the very end of the year. The opening of these stations coincides nicely with the market availability of the 12 and 13 liter truck engines which I mentioned earlier. Most of the stations are located at truck stops with our partner Pilot Flying J. As we anticipated, the competitive landscape of the natural gas vehicle fueling market has begun to evolve. We believe the emergence of others in this space is a positive validation of our efforts.Read the rest of this transcript for free on seekingalpha.com