There are multiple routes to travel from Chennai to Tirupati by car. The most travelled and the shortest route is via Poonamalle / Thiruvallur / Puttur.
Chennai to Tirupati Route 1: Chennai - Porur - Poonamalle - Thiruvallur - Thiruthani - Puttur - Tirupati (135 KM)
It is mostly a 4-lane highway till Thiruvallur, except for a couple of sub-urban sections where the road is 2-lane. From Thiruvallur, it is a 2-lane road till Thiruthani and then the road becomes 4-lane again. This route passes through many small towns and there are quite a few speed-breakers on the road. So one would need to drive carefully and at a slower pace of 50-60 KMPH.
Instead of Thiruthani, which I last heard was in a bad shape, you may also take the Uttukkottai route via NH 205 till Puttur. It is again a 2-lane highway.
Chennai to Tirupati Route 2: Chennai -Porur - Periyapalayam - Uttukkottai - Puttur - Tirupati (140 KM)
The best route from Chennai to Tirupati in terms of road condition is the one via Tada / Srikalahasti / Renigunta.
Chennai to Tirupati Route 3: Chennai - Porur - Tada - Srikalahasti - Renigunta - Tirupati (148 KM)
Although it is around 15 KM longer than the Poonamalle route, the condition of the road is superb and driving on this tarmac is a pleasure. It passes through parts of the Eastern Ghats mountain ranges and offers unparalleled scenic beauty. Also the traffic is less compared to the other routes. If you are travelling in day time, then I would suggest you to take this route to enjoy the excellent scenic backdrop.
Finally, if you are staying in the Tambaram side, then perhaps you could try this route -
Chennai to Tirupati Route 4: Chennai - Tambaram - Sriperumbudur - Thrivallur - Thiruthani - Puttur - Tirupati (155 KM)
The condition of the road was good when I last travelled in June 2014. Not sure about the recent updates.
It is safe to drive from Chennai to Tirupati at night. The only problem can be people's reluctance to use dipper at night - which is more or less a common problem in the entire South India.
Regards,
Deb