# Restore the measured pavement exposure default · r459

The viewer's `CITY_ROAD_SURFACE_GAIN` had regressed to `1.0`, even though the
same-camera r313 comparison measured and documented `1.6` as the packaged
default. The code now defaults to `1.6` again. The `cityRoadGain` URL override
is unchanged, and the adjustment remains a preview exposure correction rather
than a recovered retail light constant.

Two host Chrome/WebGL2 captures use the same packaged L4RA Route 450 start,
camera, radius 80, player car, city lighting, and source scene. Only
`cityRoadGain` differs. At `1.0`, the mid-road crop `(700,280)–(900,380)` has
mean RGB `(97.7,100.9,102.0)`; at `1.6` it is `(121.8,125.7,127.1)`. The
near-road crop `(390,310)–(470,410)` changes from `(133.1,111.0,108.2)` to
`(134.6,112.6,109.9)` because it includes the same yellow marking. Source
yellow double lines and white dashed lane paint remain visible; no marking
geometry or texture was changed. The buildings and vehicle are unaffected by
the road-only uniform. Both views reached `Traffic preview ready`; Chrome
reported no page exceptions or console errors.

- Baseline, gain 1.0: [614-r459-road-gain-baseline.png](../webgl-city/review/images/614-r459-road-gain-baseline.png)
- Restored default, gain 1.6: [615-r459-road-gain-restored.png](../webgl-city/review/images/615-r459-road-gain-restored.png)
- Viewer change: `CITY_ROAD_SURFACE_GAIN` default in `webgl-city/viewer.js`.