According to this sub-regulation, “a speakerphone is a device that enables use of the phone without holding it, providing that if the device is installed on the phone, the phone will be positioned in the vehicle in a stable manner that prevents it from falling”. For the regular mobile phone instrument in the vehicle, it is advisable to install an antenna outside the vehicle and not inside it, and to prefer wire connections between the phone and the speaker over use of a blue tooth.
Note: Although it is true that cell phones emit low frequency magnetic fields that can be measured in milliGauss, they also emit high frequency microwave radiation which is what all the concern (and publicity) is about, and which the products below are designed to shield. Many clients have contacted us seeking a shield for BOTH magnetic fields and microwaves for their phone. Such a shield does not currently exist. To reduce your exposure to BOTH types of radiation, use an airtube headset and keep the phone itself at a distance.
The energy of electromagnetic radiation is determined by its frequency; ionizing radiation is high frequency, and therefore high energy, whereas non-ionizing radiation is low frequency, and therefore low energy. The NCI fact sheet Electromagnetic Fields and Cancer lists sources of radiofrequency radiation. More information about ionizing radiation can be found on the Radiation page.