Following the LSST observation simulator with the assumed survey parameters summarized in Table 1 of @Collett15, we have generated a realistic population of galaxies lensed by early-type galaxies, assuming distributions of velocity dispersions and Einstein radii similar to the SL2S sample [@Sonnenfeld13]. The velocity dispersion function of the lenses in the local Universe follows the modified Schechter function [@Sheth03] $$\label{stat2} \frac{d n}{d \sigma}= n_*\left(
\frac{\sigma}{\sigma_*}\right)^\alpha \exp \left[ -\left(
\frac{\sigma}{\sigma_*}\right)^\beta\right] \frac{\beta}{\Gamma
(\alpha/\beta)} \frac{1}{\sigma} \, ,$$ where $\alpha$ is the low-velocity power-law index, $\beta$ is the high-velocity exponential cut-off index, $n_*$ is the integrated number density of galaxies, and $\sigma_*$ is the characteristic velocity dispersion. In this paper, we use the measurement of velocity dispersion function (VDF) for local early-type galaxies, based on the much larger SDSS Data Release 5 data set [@Choi07]. See @Cao12b for discussion about such choice in view of other data on velocity dispersion distribution functions. Currently, it was found that simple evolutions do not significantly affect the the appealing results based on lensing statistics, especially those from the early-type galaxy number counts [@Im02] and the redshift distribution of early-type lens galaxies [@Ofek03]. Therefore, it is assumed in our analysis that the normalization and shape of the velocity 