The document summarizes interviews conducted with 12 car drivers in Mumbai to understand interior lighting needs. Key findings include a need for cabin lights on the roof and passenger seats, as well as reading lights. Recommendations are made for light positioning, intensity, battery saving features, and additional lighting in footwells and door areas. The goal is to design an interior lighting system that meets user needs for nighttime safety and visibility.

1. INTERIOR LIGHTING SYSTEMS IN VEHICLES
INTERVIEW ANALYSIS & REPORT
Sandeep Supal
JULY 25,2009
Introduction
On July 14-22, 2009, I interviewed about 12 people primarily the car drivers in Mumbai as a
follow up to the project for designing the interior lighting systems for Mahindra Scorpio under
Prof. Kishor Munshi at IDC, IIT Bombay. The interview was done to identify the present
scenario of interior lighting system in Indian vehicle & identifying the needs of the user.
Through the interview we will able to identify some common issues for the drivers & the target
user.
Findings:
The main subjects of the interview are the drivers of the vehicle & most of them are specific
group of driver who drive rented vehicles. The interview question sheet is attached along with
consist of questions that mainly imply the intensity, usage, problems & requirements of various
possibilities of interior lighting along with a caselet & customer specifications. The lighting
system is to be designed for the night usage & safety.
The interview sheets are attached as appendices to the report.
Methodology
The project started with the identification of interior lighting possibilities in vehicle exemplifying
the places & usage of various interior lights inside the vehicle. On basis of this identification a
Questionnaire is designed for interviewing people who use interior lights frequently & find areas
where the present lighting lacks.
A pilot interview is done with a driver of rented car to analyze the susceptibility of the
Questionnaire and its revival. After revising the questionnaire a group of people is formulated to
be the subjects of the interview [drivers of rented cars who drive day in & day out].The interview
is analyzed and the following recommendations are suggested for the design of the interior
lighting system.

2. Recommendations for design of interior lighting:
 The positioning of cabin light is the main area of research for the design as the subjects feels the
need of cabin light on the roof top near driver in the front as well as on top of passenger seats at
the back {expected even in hatchback vehicles}.
 There should not be any conflict in positioning the cabin light with rear mirror leading to bad
design for the user.
 The intensity of the cabin light should be enough for readability of maps, books etc so the
subjects suggest the usage of tube lights & LEDs for the cabin light. The source of cold light is
favored by many users inside the vehicle. White and yellow interior light colors are suggested by
many users.
 Since the usage of cabin light is rare during daytime & is about 5-10 min at night the application
of knob {switching} mechanism is the need of the hour to save the battery power.
 Automated light {Diminishing light} is one of the technical phenomenons the user expects from
design.
 Reading light is required to many users for passenger seats.
 Simplicity & Professional are the main supported metaphors for the lighting system inside the
vehicle. Light design should be minimalistic.
 Light colored interiors {light reflectors} are favored over dark colored interiors by many subjects.
 Current problem of lighting system is the level of illumination which should be high according to
many users but they also expect the less usage of car battery at the same time so its recommended
that some external source should be used for interior lighting system like lithium ion batteries ,Ni-
Cd batteries etc.
 Footwell lighting requirement is supported by many subjects for safety & handling inside the
vehicle. The placement of such lighting system should be under the seats or array of light the
edges of rubber foot bed. The user expects some colors like purple or reddish-yellow for
illuminating the footwell light for stylish glow.
 The caselet suggests that the users want detectable dim light inside vehicle (switched on) for
night driving for safety and perceive the vehicle coming from the front.
 Decorative color lights are suggested by many users for dashboard lighting & creating a visual
ambience in the interiors of vehicle but pertaining to the functionality of the lighting system.
 Door light {line source} is required only in those public vehicle where new passengers cant
operate the door opening mechanism.

3. INTERIORS LIGHTING POSSIBILITIES
Sr. TYPES OF INTERIOR PLACE USAGE
LIGHTS
1 General /Dome lights Top of cabin & also at the Visibility inside the dome ,at
middle front top of cabin stoppages, operating inside the
for driver cabin
2 Vanity lights Lights on the sun visors Used as make up light
3 Dashboard lights Behind the instrument Reading the instrument cluster
cluster box
4 Glove box lights Inside the glove box For illuminating the A/C, Music
system, controls, keeping objects
5 Storage compt. lights Inside storage For storing luggage at night
compartments
6 Reading lights Same as in airplanes over Used for reading , mainly found in
readers sits or above side chauffer driven vehicles
mirror
7 Pocket Door lights At the front of pocket door For accessing exit points{locks/
door controls} at night
8 Footwell lights Under the seat /near to For visibility of foot controls at
footrest nights
9 Puddle lights Under the door sides at For stoppage locations in dark used
exterior points in race cars
10 Threshold lights Working lights under the Working light for mechanic
car