Local dimming LCDs with a matrix backlight unit (BLU) are favored by many car manufacturers for high quality and low power displays. Automotive application sets high requirement like safety standard, whereas the temperature range and lifespan are wide. The contents are mostly HMIs with high contrast and circular structures. Thus, the two key components, BLU and the local dimming algorithm need to be adopted to automotive needs/demands and shall be jointly optimized. In this paper, the BLU design aspects and specification are described. Specific features relevant for automotive, like black corners and containment against LED outage, are introduced. The tradeoff between performance and cost is lifted. With a BLU with 384 LEDs, the contrast ratio may be enhanced by a factor of 20, while an average power saving ratio of 50% can be achieved.