Abstract:
An improved traffic accident preventing system to alarm both a driver on vehicle and pedestrian each other using a radio communication unit when they are located close. This system also provides a traffic monitoring and control system using communication between vehicle, pedestrian with communication unit and radio unit equipped by roadside, in which a traffic management center can send information to a specific vehicle and pedestrian with communication unit, and also receive information from them.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention relates to a system for preventing traffic accidents between vehicles and pedestrians; and more particularly, to such a system utilizing radio communication therebetween. 
     2. Discussion of Prior Art 
     Heretofore, a radar system on a automotive vehicle can detect a pedestrian in front of a automotive vehicle, but field of vision of a radar system is as narrow as a that of a driver of a vehicle, so it is impossible to detect a pedestrian who suddenly rushes out in front of a vehicle in advance. And a radar system uses a millimeter wave, which has a sharp directivity and goes straightly, so a radar system cannot detect a pedestrian behind edge of intersection. 
     Examples of the related are comprise: U.S. Pat. No. 4,543,577; U.S. Pat. No. 5,522,509 and U.S. Pat. No. 6,081,223; Simon et al , Spread Spectrum Communication Handbook, Revised Edition, McGraw-Hill, 1994; and Morris et al, Airborn Pulsed Doppler Radar, 2nd Edition, Artech House, 1996. However, the art leaves much to be desired in terms of traffic safety, prevention of accidents, and use of latest technology to improve the quality of life with respect to vehicle traffic. 
     Heretofore, traffic management center monitors vehicles by using DSRC, ultrasonic beacon and optical beacon using communication units both on a vehicle and on roadside. In this case units on vehicles are relatively expensive. 
     OBJECTS 
     Accordingly several objects of our invention, it is possible to alarm and notify to a driver that a pedestrian locates near a vehicle, and call driver&#39;s attention to a pedestrian, even if a pedestrian is out of a driver&#39;s view field, and to prevent traffic accident. It is also possible to call pedestrian&#39;s attention to an approaching vehicle. 
     And it is also possible to alarm and notify to a driver that a pedestrian locates behind edge of intersection and to call driver&#39;s attention, so a driver can prepare for pedestrian&#39;s rushing suddenly out in front of a vehicle in advance. 
     And it is also possible to support investigation for the cause of the traffic accident by recording ID code of a vehicle and/or pedestrian, with time and location by each unit on a vehicle and with pedestrian. 
     Accordingly several objects of our invention, traffic management center can communicate vehicles using relatively cheep on-vehicle unit and can monitor traffic values, vehicle speeds, a route of a specific vehicle, so as to control traffic and keep appropriate traffic flow. 
     Further objects and advantages of our invention will become apparent from a consideration of the drawings and ensuing description thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features and advantages of the present invention will be appreciated from the following description and drawings in which like reference numerals designate corresponding elements and in which: 
     FIG. 1 shows the first preferred embodiment according to the present invention. 
     FIGS. 2A and 2B show the potable resonant tag that pedestrian  103 ,  107  in FIG. 1 carries by. 
     FIG. 3 shows the vehicle transmitter/receiver  102  in FIG.  1 . 
     FIG. 4 shows the second preferred embodiment according to the present invention. 
     FIG. 5 shows the vehicle transmitter/receiver  402  in FIG.  4 . 
     FIG. 6 shows the third preferred embodiment according to the present invention. 
     FIG. 7 shows the vehicle transmitter/receiver  602  in FIG. 6 on the vehicle  601  in FIG.  6 . 
     FIG. 8 shows the fourth preferred embodiment according to the present invention. 
     FIG. 9 shows the vehicle transmitter/receiver  802  in FIG. 8 on the vehicle  801  in FIG.  8 . 
     FIG. 10 shows the potable transmitter/receiver  804  in FIG. 8 which the pedestrian  803  in FIG. 8 carries by. 
     FIG. 11 shows the fifth preferred embodiment according to the present invention. 
     FIG. 12 shows the vehicle transmitter/receiver  1102  in FIG.  11 . 
     FIG. 13 shows the roadside transmitter/receiver  1103  in FIG.  11 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows the first preferred embodiment according to the present invention. 
     In FIG. 1, numeral  101  denotes a vehicle. 
     Numeral  102  denotes vehicle transmitter/receiver on a vehicle transmitting predetermined frequency signals and receiving echo signals from potable resonant tag that pedestrian located near the vehicle carries by. 
     Numeral  103  denotes pedestrian located near the vehicle  101 . 
     Numeral  104  denotes potable resonant tag that pedestrian  103  located near the vehicle  101  carries by. 
     Numeral  105  denotes predetermined frequency signals transmitted by vehicle transmitter/receiver  102 . 
     Numeral  106  denotes a echo signal from a potable resonant tag  104 . 
     When vehicle transmitter/receiver  102  receives the echo signals then an alarm notifying to driver of vehicle  101  that there is a pedestrian  103  located near vehicle  101 . 
     Numeral  107  denotes a pedestrian located far distance from the vehicle  101 . 
     Numeral  108  denotes potable resonant tag that pedestrian  107  carries by. 
     Numeral  109  denotes predetermined frequency signals transmitted by vehicle transmitter/receiver  102  and attenuated when it reached a potable resonant tag  108 . 
     Numeral  110  denotes echo signal from a potable resonant tag  108  and can not be received at vehicle transmitter/receiver by attenuation, so vehicle transmitter/receiver  102  does not produce an alarm. 
     FIGS. 2A and 2B show the potable resonant tag that pedestrian  103 ,  107  in FIG. 1 carries by. 
     FIG. 2A shows electrical equivalent circuit of the potable resonant tag. 
     In FIG. 2A numeral  202  denotes electric capacitance valued C. 
     Numeral  203  denotes electric inductance valued L. 
     Numeral  201  denotes a equation defining a resonant frequency with C and L, which is equal to the frequency of the predetermined frequency signals. 
     FIG. 2B shows the feature of the potable resonant tag. 
     Numeral  204  denotes an insulator such as paper. 
     Numeral  205  denotes a electric inductance formed by printing a conductance such a aluminum foil in a coil state on the insulator  204 . 
     Numeral  206  denotes a electric capacitance formed by printing a conductance such a aluminum on both side of the insulator  204 . 
     Both a electric inductance  205  and a electric capacitance are connected parallel and forms a resonant unit. 
     FIG. 3 shows the vehicle transmitter/receiver  102  in FIG.  1 . 
     In FIG. 3, numeral  301  denotes vehicle transmitter generating a predetermined frequency signal. 
     Numeral  302  denotes an antenna. 
     Numeral  305  denotes the predetermined frequency signals which generated by vehicle transmitter  301  and transmitted by the antenna  302 . 
     Numeral  306  denotes the echo signal of the predetermined frequency signals  305  reflected by the potable resonant tag  104  in FIG. 1 carried by the pedestrian  103  in FIG. 3, when the pedestrian  103  in FIG. 1 is located near the vehicle  101  in FIG.  1 . 
     Numeral  303  denotes vehicle receiver unit receiving the echo signal  306  through the antenna  302 . 
     Numeral  304  denotes the alarm unit generating an alarm to a driver on vehicle notifying that there is a pedestrian who carries by the potable resonant tag  104  in FIG. 1 near a vehicle  101  in FIG. 1 when the vehicle transmitter/receiver receives the echo signal  306 . 
     FIG. 4 shows the second preferred embodiment according to the present invention. 
     In FIG. 4, numeral  401  denotes a 1st vehicle. 
     Numeral  402  denotes a 1st vehicle transmitter/receiver on the 1st vehicle  401 . 
     Numeral  403  denotes a 1st pedestrian. 
     Numeral  404  denotes a 1st potable resonant tag which carried by the 1st pedestrian  403 , and which reflects echo signal of transmitted signal by the 1st vehicle transmitter/receiver  402  when the 1st pedestrian  403  is located near the 1st vehicle  401 . 
     Numeral  405  denotes signals transmitted by the 1st vehicle transmitter/receiver  402 . 
     Numeral  406  denotes echo signal from the potable resonant tag  404 . 
     When the 1st vehicle transmitter/receiver  402  receives the echo signal  406 , it produces an alarm for the driver on the 1st vehicle notifying that the 1st pedestrian  403  is located near the 1st vehicle  401 . 
     In this case both the signals  406  and the echo signal  406  are modulated by the same pseudo noise, so the 1st vehicle transmitter/receiver  402  demodulates the echo signal  406  and produces an alarm. 
     Numeral  407  denotes a 2nd vehicle. 
     Numeral  408  denotes a 2nd vehicle transmitter/receiver on the 2nd vehicle  407 . 
     Numeral  411  denotes a 2nd pedestrian. 
     Numeral  412  denotes a 2nd potable resonant tag which carried by the 2nd pedestrian  411 . 
     Numeral  409  denotes transmitted signal by the 2nd vehicle transmitter/receiver  408  and received by the 1st vehicle transmitter/receiver  402 . 
     Numeral  410  denotes transmitted signal by the 2nd vehicle transmitter/receiver  408  and reflected by the 2nd potable resonant tag  412 . 
     Numeral  413  denotes echo signal of the signal  410  reflected by the 2nd potable resonant tag  412 . 
     Even when the 2nd vehicle  407  is approaching to the 1st vehicle  401  and the 1st vehicle transmitter/receiver  402  receives the signal  409 , the 1st vehicle transmitter/receiver  402  doesnt demodulate the signal and does not produce an alarm, because the signal  409  is moderated by different pseudo noise of the let vehicle transmitter/receiver. 
     When the 1st vehicle transmitter/receiver  402  receives the echo signals  413 , the 1st vehicle transmitter/receiver  402  doesnt demodulate the signal and does not produce an alarm, because the echo wave  413  is moderated by different pseudo noise of the 1st vehicle transmitter/receiver. 
     FIG. 5 shows the vehicle transmitter/receiver  402  in FIG.  4 . 
     In FIG. 5, numeral  501  denotes a pseudo noise generating unit which generates a unique pseudo noise for a vehicle  401  in FIG.  4 . 
     Numeral  502  denotes a vehicle spread-spectrum transmitter which modulates a signal using the pseudo noise generated by the pseudo noise generating unit  501 . 
     Numeral  503  denotes an antenna which transmits a spread-spectrum signal generated by the vehicle spread-spectrum transmitter  502  as a signal  506 . 
     Numeral  504  denotes a vehicle spread-spectrum receiver which demodulates a echo signal  507 , which reflected by the potable resonant tag  404  in FIG.  4  and received by the antenna  503 . 
     Numeral  505  denotes an alarm unit producing an alarm to the driver on vehicle  401  notifying that there is the pedestrian  403  near the vehicle  401  when the vehicle transmitter/receiver  500  receives the echo signal  507  which modulated by the same pseudo noise as one which generated by the pseudo noise generating unit  501 . 
     An alarm unit  505  does not generate an alarm to the driver on vehicle  401  even when the vehicle transmitter/receiver  600  receives echo signal from other than the vehicle transmitter/receiver  500 , because of modulated by different pseudo noise from one that generated by the pseudo noise generating unit  501 . 
     FIG. 6 shows the third preferred embodiment according to the present invention. 
     In FIG. 6, numeral  601  denotes a vehicle. 
     Numeral  602  denotes a vehicle transmitter/receiver on the vehicle  601  which can select a frequency of receiving signals. 
     Numeral  605  denotes a moving direction of the vehicle  601 . 
     Numeral  606  denotes a moving velocity of the vehicle  601 . 
     Numeral  604  denotes a predetermined frequency signals in frequency of transmitted by vehicle transmitter/receiver  602 . 
     Numeral  610  denotes a 1st pedestrian located in forward of moving direction for the vehicle  601 . 
     Numeral  611  denotes an echo signal from a 1st potable resonant tag  603 . 
     Numeral  603  denotes a 1st potable resonant tag, which receives the predetermined frequency signals  604 , resonates, and reflect the echo signal  611 . 
     The vehicle transmitter/receiver  602  receives the echo signal  611  which has increased frequency ff by Doppler effect of moving vehicle  601  in velocity v when the 1st pedestrian  610  is located near in forward of moving direction for the vehicle  601 , and recognizes and notifies to the driver of the vehicle  601  that the 1st pedestrian  610  is located near in forward of moving direction for the vehicle  601  because of the frequency of the echo signal  611  ff is higher than that of the predetermined frequency signals  604  in frequency fo. 
     Numeral  620  denotes a 2nd pedestrian located at right angles to moving direction for the vehicle  601 . 
     Numeral  621  denotes an echo signal from a 2nd potable resonant tag  622 . 
     Numeral  622  denotes a 2nd potable resonant tag, which receives the predetermined frequency signals  604 , resonates, and reflect the echo wave  621 . 
     The vehicle transmitter/receiver  602  receives the echo wave  621  which has the same frequency fs (=fo) as frequency of the predetermined frequency signals  604  when a 2nd pedestrian  620  is located near at right angles to moving direction for the vehicle  601 , and recognizes and notifies to the driver of the vehicle  601  that the 2nd pedestrian  620  is located near at right angles to moving direction for the vehicle  601  because of the frequency of the echo wave  621  fs is the same as that of the predetermined frequency signals  604  in frequency fo. 
     Numeral  630  denotes a 3rd pedestrian locating in backward of moving direction for the vehicle  601 . 
     Numeral  631  denotes an echo signal from a 3rd potable resonant tag  632 . 
     Numeral  633  denotes a 3rd potable resonant tag, which receives the predetermined frequency signals  604 , resonates, and reflect the echo signal  631 . 
     The vehicle transmitter/receiver  602  receives the echo signal  631  which has decreased frequency fr by Doppler effect of moving vehicle  601  in velocity v when the 3rd pedestrian  630  is located near in backward of moving direction for the vehicle  601 , and recognizes and notifies to the driver of the vehicle  601  that the 3rd pedestrian  630  is located near in backward of moving direction for the vehicle  601  because of the frequency of the echo signal  631  fr is lower than that of the predetermined frequency signals  604  in frequency fo. 
     FIG. 7 shows the vehicle transmitter/receiver  602  in FIG. 6 on the vehicle  601  in FIG.  6 . 
     In FIG. 7, numeral  715  denotes an antenna. 
     Numeral  701  denotes a vehicle transmitter which transmits a predetermined frequency signals in frequency of through the antenna  715 . 
     Numeral  711  denotes a predetermined frequency signal in frequency of transmitted by the vehicle transmitter  701 . 
     Numeral  712  denotes a echo signals in frequency fx from the potable resonant tag  603 ,  622 ,  632  in FIG.  6 . 
     Numeral  702  denotes a vehicle receiver which receives an echo signal  712  through the antenna  715 . 
     Numeral  703  denotes a frequency detector which selects receiving frequency and so as to detect the frequency of the echo signals  712 . 
     Numeral  705  denotes a signal select switch. 
     Numeral  704  denotes a mixer unit which converts a frequency fx of the echo signals  712  from the vehicle receiver  702  into a frequency fm by subtracting the frequency fx from a frequency selected by the signal select switch  705 . 
     Numeral  709  denotes a frequency filter which passes through only a signal in frequency fm. 
     Numeral  710  denotes a alarm unit which produces an alarm to the driver on vehicle  601  in FIG. 6 only when the signal from the mixer unit  704  passes through the frequency filter  709 . 
     Numeral  706  denotes a 1st local oscillation unit which generates a signal in frequency (ff-fm). 
     Numeral  707  denotes a 2nd local oscillation unit which generates a signal in frequency (fo-fm). 
     Numeral  708  denotes a 3rd local oscillation unit which generates a signal in frequency (fr-fm). 
     The signal selection switch  705  selects one of the three signals, (ff-fm) generated by the 1st local oscillation unit  706 , (fo-fm) generated by the 2nd local oscillation unit  707 , (fr-fm) generated by the 3rd local oscillation unit  708 , and transfers it to the mixer unit  704 . 
     Herein of means a frequency of the predetermined frequency signal  711  transmitted by the vehicle transmitter  701 , ff means a increasing frequency of Doppler effect when the vehicle  601  in FlG.  6  is approaching to the potable resonant tag  603  in FIG. 6 by velocity v, and fr means a decreasing frequency of Doppler effect when the vehicle  601  in FIG. 6 is departure from the potable resonant tag  603  in FIG. 6 by velocity v, and fm means a frequency only which the frequency filter  709  passes through. 
     Numeral  713  denotes a velocity measurement unit which measures a velocity of the vehicle  601  in FIG.  6 . 
     Numeral  714  denotes a calculation unit which calculates ff=fo×(c+2v)/{square root over ( )}4(c{circumflex over ( )}2−v{circumflex over ( )}2), fr=fo×(c−2v)/{square root over ( )}4(c{circumflex over ( )}2−v{circumflex over ( )}2) using velocity value v measured by the velocity measurement unit  713  and controls oscillation frequencies of both the 1st local oscillation unit  706  and the 3rd local oscillation unit  708 . 
     The signal selection switch  705  selects one of the following three modes; 
     a) The alarm unit  710  produces an alarm to the driver only when a pedestrian is located near in forward of moving direction for the vehicle  601  in FIG.  6 . 
     b) The alarm unit  710  produces an alarm to the driver only when a pedestrian is located near at right angles to moving direction for the vehicle  601  in FIG.  6 . 
     c) The alarm unit  710  produces an alarm to the driver only when a pedestrian is located near in backward of moving direction for the vehicle  601  in FIG.  6 . 
     FIG. 8 shows the fourth preferred embodiment according to the present invention. 
     In FIG. 8, numeral  801  denotes a vehicle. 
     Numeral  802  denotes a vehicle transmitter/receiver on the vehicle  801 . 
     Numeral  805  denotes a vehicle signal which transmitted by the vehicle transmitter/receiver  802 . 
     Numeral  803  denotes a pedestrian. 
     Numeral  806  denotes a pedestrian signal. 
     Numeral  804  denotes a potable transmitter/receiver which is carried by the pedestrian  803  and receives the vehicle signal  805 , detects pseudo noise from the vehicle signal  805 , modulates signal by the detected pseudo noise, and transmits the pedestrian signal  806 . The potable transmitter/receiver  804  transmits the pedestrian signal  806  which is spread-spectrum modulated by the same pseudo noise as that of the vehicle signal  805 , when the pedestrian  803  is located near the vehicle  801 . 
     When the vehicle transmitter/receiver  802  receives the pedestrian signal  806  modulated by the same pseudo noise as that of the vehicle signal  805  by transmitted by itself, the vehicle transmitter/receiver  802  produces an alarm to the driver on vehicle  801  notifying that there is the pedestrian  803  near the vehicle  801 . The vehicle transmitter/receiver  802  does not produce an alarm when the pedestrian  803  isn&#39;t located near the vehicle  801 , because the vehicle signal  805  does not arrive at the potable transmitter/receiver  804  by propagation attenuation, so the potable transmitter/receiver  804  does not transmitted the pedestrian signal  806 . 
     The pedestrian signal  806  is modulated by the same pseudo noise as that of the vehicle signal  805 , so the vehicle transmitter/receiver  802  demodulates the pedestrian signal  806  and produces an alarm. 
     When the potable transmitter/receiver  804  receives the vehicle signal  805 , the potable transmitter/receiver  804  produces an alarm to the pedestrian  803  notifying that there is the vehicle  801  near the pedestrian  803 . The potable transmitter/receiver  804  does not produce an alarm when the vehicle  801  isn&#39;t located near the pedestrian  803 , because the vehicle signal  805  does not arrive at the potable transmitter/receiver  804  by propagation attenuation. 
     FIG. 9 shows the vehicle transmitter/receiver  802  in FIG. 8 on the vehicle  801  in FIG.  8 . 
     In FIG. 9, numeral  900  denotes a vehicle transmitter/receiver. 
     Numeral  901  denotes a pseudo noise generating unit which generates a unique pseudo noise corresponding to a vehicle ID code of the vehicle  801  in FIG.  8 . 
     Numeral  902  denotes a vehicle spread-spectrum transmitter which modulates a signal using the pseudo noise generated by the pseudo noise generating unit  901 . 
     Numeral  903  denotes an antenna which transmits a spread-spectrum signal generated by the vehicle spread-spectrum transmitter  902  as a vehicle signal  908 . 
     Numeral  904  denotes a vehicle spread-spectrum receiver which demodulates a pedestrian signal  909  using the pseudo noise generated by the pseudo noise generating unit  901 , which transmitted by the potable transmitter/receiver  804  in FIG.  8 . 
     Numeral  906  denotes an alarm unit which produces an alarm to the driver on vehicle  801  in FIG. 8 when the vehicle spread-spectrum receiver  904  demodulates the pedestrian signal  909 . 
     When the antenna  903  receives the pedestrian signal  909  which is response signal of the other vehicle transmitter/receiver than the vehicle transmitter/receiver  802  in FIG. 8, the vehicle spread-spectrum receiver  904  does not demodulate the pedestrian signal  909  because its pseudo noise is difference from that generated by the pseudo noise generating unit  901 , so the vehicle spread-spectrum receiver  904  does not produce a trigger signal to the alarm unit  906 , then the alarm unit  906  does not produce an alarm. 
     Numeral  905  denotes a pedestrian ID code recognition unit which demodulates the pedestrian ID code of the pedestrian  803  in FIG. 8 from an output signal of the vehicle spread-spectrum receiver  904 . 
     Numeral  907  denotes a display unit; which notifies the pedestrian ID code of the pedestrian  803  to the driver on vehicle  801  in FIG.  8 . 
     FIG. 10 shows the potable transmitter/receiver  804  in FIG. 8 which the pedestrian  803  in FIG. 8 carries by. 
     In FIG. 10, numeral  1003  denotes an antenna. 
     Numeral  1004  denotes a potable spread-spectrum receiver which receives the vehicle signal  1010  through the antenna  1003 . 
     Numeral  1007  denotes an alarm unit which produce an alarm to the pedestrian  803  in FIG. 8 notifying that there is a vehicle near the pedestrian  803  in FIG. 8 when the potable spread-spectrum receiver  1004  receives the vehicle signal  1010 . 
     Numeral  1005  denotes a pseudo noise detection unit which detect a pseudo noise from the vehicle signal  1010 . 
     Numeral  1011  denotes a vehicle ID code recognition unit which converts the pseudo noise into a vehicle ID code. 
     Numeral  1006  denotes a display unit which notifies the vehicle ID code to the pedestrian  803  in FIG.  8 . 
     Numeral  1001  denotes a pedestrian ID code generating unit which generates a pedestrian ID code of the pedestrian  803 . 
     Numeral  1002  denotes a potable spread-spectrum transmitter which modulates the pedestrian ID code using the pseudo noise detected by the pseudo noise detection unit  1005 . 
     The potable spread-spectrum transmitter  1002  uses the pseudo noise detected from the vehicle signal  1010  by the pseudo noise detection unit  1005  and so the pedestrian signal  1009  is modulated by the same pseudo noise as that of the vehicle signal  1010 , then vehicle transmitter/receiver  802  in FIG. 8 demodulates the pedestrian signal  1009 . 
     FIG. 11 shows the fifth preferred embodiment according to the present invention. 
     In FIG. 11, numeral  1000  denotes a road. 
     Numeral  1103  denotes a roadside transmitter/receiver which equipped at roads. 
     Numeral  1101  denotes a vehicle. 
     Numeral  1102  denotes a vehicle transmitter/receiver. 
     Numeral  1104  denotes a vehicle signal which is transmitted by the vehicle transmitter/receiver  1102  and is received by the roadside transmitter/receiver  1103 . 
     Numeral  1105  denotes a roadside signal which is transmitted by the roadside transmitter/receiver  1103  and is received by the vehicle transmitter/receiver  1102 . 
     When the vehicle  1101  is approaching to the roadside transmitter/receiver  1103 , the roadside transmitter/receiver  1103  receives the vehicle signal  1104  and transmits the roadside signal  1105  as a response signal. 
     The roadside transmitter/receiver  1103  detects a pseudo noise from the vehicle signal  1104  and then the roadside transmitter/receiver  1103  converts the pseudo noise into the vehicle ID code of the vehicle  1101  in FIG.  11 . The roadside transmitter/receiver  1103  transmits the roadside signal  1105  modulated by the pseudo noise detected from the vehicle signal  1104 . 
     FIG. 12 shows the vehicle transmitter/receiver  1102  in FIG.  11 . 
     In FIG. 12, numeral  1200  denotes a vehicle transmitter/receiver. 
     Numeral  1201  denotes a pseudo noise generating unit which generates a unique pseudo noise corresponding to a vehicle ID code of the vehicle  1101  in FIG.  11 . 
     Numeral  1202  denotes the vehicle spread-spectrum transmitter which modulates a signal using the pseudo noise generated by the pseudo noise generating unit  1201 . 
     Numeral  1203  denotes an antenna. 
     Numeral  1207  denotes the vehicle signal which is transmitted by the vehicle spread-spectrum transmitter  1202  through the antenna  1203 . 
     Numeral  1208  denotes the roadside signal which is transmitted by the roadside transmitter/receiver  1103  in FIG. 
     Numeral  1204  denotes a vehicle spread-spectrum receiver which demodulates the roadside signal  1208  using the pseudo noise generated by the pseudo noise generating unit  1201 . 
     Numeral  1205  denotes an information recognition unit which demodulates an information from the output signal of the vehicle spread-spectrum receiver  1204 . 
     Numeral  1206  denotes a display unit which notifies the information to the driver of the vehicle  1101  in FIG.  11 . 
     When the antenna  1203  receives the roadside signal  1208  which is response signal of the other vehicle transmitter/receiver than the vehicle transmitter/receiver  1102  in FIG. 11, the vehicle spread-spectrum receiver  1204  does not demodulate the roadside signal  1208  because its pseudo noise is difference from that generated by the pseudo noise generating unit  1201 , so the vehicle spread-spectrum receiver  1204  does not transfer a signal to the information recognition unit  1205 , then the display unit  1206  does not display any information. 
     FIG. 13 shows the roadside transmitter/receiver  1103  in FIG.  11 . 
     In FIG. 13, numeral  1300  denotes the roadside transmitter/receiver  1103  in FIG.  11 . 
     Numeral  1309  denotes a roadside signal which is transmitted by the roadside transmitter/receiver  1300 . 
     Numeral  1310  denotes a vehicle signal which is received by the roadside transmitter/receiver  1300 . 
     Numeral  1303  denotes an antenna. 
     Numeral  1304  denotes a roadside spread-spectrum receiver which receives the vehicle signal through the antenna  1303 . 
     Numeral  1305  denotes a pseudo noise detecting unit which detect a pseudo noise from the vehicle signal  1310 . 
     Numeral  1306  denotes the vehicle ID recognition unit which converts a signal from the pseudo noise detecting unit  1305  into the vehicle ID code. 
     Numeral  1307  denotes a communication unit. 
     Numeral  1311  denotes a communication network. 
     Numeral  1312  denotes a management center. 
     The communication unit  1307  transmits the vehicle ID code to the management center  1312  on the communication network  1311 . 
     Numeral  1302  denotes a roadside spread-spectrum transmitter which receives the information to be notified for the vehicle driver from the communication unit  1307 , and modulates the information using the pseudo noise detected by the pseudo noise detecting unit  1305 , and transmits it as the roadside signal  1309  through the antenna  1303 . 
     The roadside spread-spectrum transmitter  1302  uses the pseudo noise detected from the vehicle signal  1310  by the pseudo noise detecting unit  1305 , so the roadside signal  1309  is modulated by the same pseudo noise as that of the vehicle signal  1310 , then vehicle transmitter/receiver  1102  in FIG. 11 demodulate that the roadside signal. 
     A management center  1312  sets and alters the information to be notified for the vehicle driver using by the communication unit  1307  and the communication network  1311 . 
     While, the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. Many other variations are possible, for example; 
     (a) A vehicle transmitter/receiver in FIGS. 3,  5 ,  7 ,  9 ,  12  and a potable transmitter/receiver in FIG. 10 can be united with a cellular phone so as to reduce costs. 
     (b) A vehicle transmitter/receiver in FIGS. 3,  5 ,  7 ,  9 ,  12  and a potable transmitter/receiver in FIG. 10 and a roadside transmitter/receiver in FIG. 13 can be connected with GPS receiver and transmit a location data with other information described above. 
     (c) A vehicle transmitter/receiver in FIGS. 3,  5 ,  7 ,  9 ,  12  and a potable transmitter/receiver in FIG. 10 and a roadside transmitter/receiver in FIG. 13 can be connected with a recorder and clock so as to save information described above. 
     It is possible to support investigation for the cause of the traffic accident to record vehicle/pedestrian ID code, time and location by each unit on a vehicle and with pedestrian. 
     (d) A potable transmitter/receiver in FIG.  10  and the roadside transmitter/receiver in FIG. 13 communicate each other. 
     Accordingly, the scope of the invention should be determined not by the embodiment illustrated, but by the appended claims and their legal equivalents.